Square Kilometer to Square Foot Converter
Convert square kilometers to square feet with our free online area converter.
Quick Answer
1 Square Kilometer = 10763910.41671 square feet
Formula: Square Kilometer × conversion factor = Square Foot
Use the calculator below for instant, accurate conversions.
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All conversion formulas on UnitsConverter.io have been verified against NIST (National Institute of Standards and Technology) guidelines and international SI standards. Our calculations are accurate to 10 decimal places for standard conversions and use arbitrary precision arithmetic for astronomical units.
Square Kilometer to Square Foot Calculator
How to Use the Square Kilometer to Square Foot Calculator:
- Enter the value you want to convert in the 'From' field (Square Kilometer).
- The converted value in Square Foot will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Area category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Square Kilometer to Square Foot: Step-by-Step Guide
Converting Square Kilometer to Square Foot involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Square Kilometer = 10763910 square feetExample Calculation:
Convert 10 square kilometers: 10 × 10763910 = 107639100 square feet
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
Need to convert to other area units?
View all Area conversions →What is a Square Kilometer and a Square Foot?
The Square Kilometer (symbol: km² or sq km) is a multiple of the square meter (m²), the base unit of area in the International System of Units (SI). It represents the area of a square whose sides measure exactly one kilometer (km) in length.
Key relationships:
- 1 km² = 1 kilometer × 1 kilometer
- 1 km = 1,000 meters (m)
- Therefore, 1 km² = (1,000 m) × (1,000 m) = 1,000,000 square meters (m²)
- 1 km² = 100 hectares (ha) (since 1 hectare = 10,000 m²)
In terms of imperial/US customary units:
- 1 km² ≈ 0.3861 square miles (mi²) - Convert km² to mi²
- 1 km² ≈ 247.1 acres (ac) - Convert km² to acres
- 1 km² ≈ 10,763,910 square feet (ft²)
Visual perspective:
- 1 km² = 100 football fields (American)
- 1 km² = ~150 soccer fields
- 1 km² = Walking distance of about 1 km × 1 km
- 10 km² = Typical small town
- 100 km² = Medium-sized city
- 1,000 km² = Large metropolitan area
Convert between area units: Square kilometer converter
and Standards
The square foot is defined as the area of a square with sides measuring exactly one international foot:
1 ft² = (1 foot)² = (12 inches)² = (0.3048 meters)²
Precise Equivalents
- 1 ft² = 144 in² (exactly)
- 1 ft² = 1/9 yd² = 0.1111... yd² (exactly)
- 1 ft² = 0.09290304 m² (exactly, by 1959 definition)
- 1 ft² = 929.0304 cm² (exactly)
- 1 ft² = 92,903.04 mm² (exactly)
- 1 acre = 43,560 ft² (exactly)
- 1 square mile = 27,878,400 ft² (exactly)
International Foot Standard (1959)
The International Yard and Pound Agreement of 1959 defined the international foot as precisely 0.3048 meters, resolving slight differences between the US survey foot and the British imperial foot. This definition makes:
1 square foot = (0.3048 m)² = 0.09290304 m² (exactly)
Before 1959, small variations existed. The US survey foot (still used in some land surveys) is defined as exactly 1200/3937 meters, making the US survey square foot = 0.09290341... m² (about 0.0004% larger—negligible for most purposes).
Symbol Variations
The square foot is represented by multiple symbols:
- ft² (most common, scientific)
- sq ft or sq. ft. (common in real estate)
- SF (architectural drawings, construction documents)
- □′ (rare, using the foot prime symbol)
All represent the same unit.
Note: The Square Kilometer is part of the metric (SI) system, primarily used globally in science and trade. The Square Foot belongs to the imperial/US customary system.
History of the Square Kilometer and Square Foot
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Origin: The square kilometer is derived directly from the kilometer, a unit of length introduced as part of the metric system, which was developed in France during the late 18th century (1790s).
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Metric System Adoption: The metric system, including the meter and its multiples like the kilometer, was created to provide a standardized, decimal-based system of measurement to replace the chaotic local units of pre-revolutionary France.
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Natural Evolution: As nations began adopting the metric system throughout the 19th and 20th centuries, the square kilometer naturally became the standard unit for expressing large geographical areas - countries, regions, cities, lakes, and forests.
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International Standardization: The need for a universal unit for geographical measurement became critical as:
- World maps and atlases were standardized
- International treaties needed land area specifications
- Global trade required consistent land measurements
- Scientific exploration needed standard area units
-
SI Standard: The International System of Units (SI), formally established in 1960, confirmed the square meter (m²) as the base unit of area. The square kilometer is a widely accepted and commonly used multiple of this base unit, consistent with SI prefixes (kilo = 1,000).
-
Global Usage Today: The square kilometer is now the predominant unit used worldwide for measuring:
- Land area of countries and territories
- Surface area of continents and islands
- Size of administrative divisions (states, provinces, counties)
- Area of cities and metropolitan regions
- Size of bodies of water (lakes, seas)
- Extent of forests, deserts, and ecosystems
- National parks and protected areas
-
Note on spelling: "Kilometer" (US) and "kilometre" (UK/International) both produce "square kilometer" and "square kilometre" respectively, both referring to the same unit: 1,000,000 m².
and Evolution
Ancient Origins: The Human Foot (3000 BCE - 1200 CE)
The foot as a length measurement dates to ancient civilizations, where it approximated the length of a human foot:
- Egyptian royal cubit: ~0.525 m, subdivided into "feet" of ~0.30 m
- Greek pous: ~0.296 m (varied by city-state)
- Roman pes: ~0.2967 m (29.67 cm)
- Medieval European feet: Varied from 0.25-0.34 m depending on region
These variations meant "square feet" were inconsistent across regions and time periods. A Roman square foot was about 88 cm² versus a medieval German square foot of up to 100 cm².
English Standardization: From Barleycorns to Royal Feet (1300-1824)
Medieval England attempted standardization through royal decrees:
- Edward I (1305): Defined the inch as "three grains of barley, dry and round, laid end to end," making a foot = 36 barleycorns
- Edward II (1324): Further refined the foot based on the royal standard at Westminster
- Weights and Measures Acts (1700s-1824): Gradually standardized the imperial foot across Britain
The Weights and Measures Act of 1824 officially defined the imperial foot and established consistency across the British Empire. This foot became the basis for square footage in British architecture, land surveying, and real estate.
American Adoption: Colonial Legacy (1600s-1959)
American colonists brought English measurement systems to the New World. After independence, the United States retained imperial units rather than adopting the metric system (despite Thomas Jefferson's advocacy for decimalization).
The US customary foot slightly diverged from the British imperial foot over time due to independent maintenance of measurement standards. By the mid-20th century, the difference was approximately 2 parts per million—tiny, but problematic for precision surveying.
The 1959 International Agreement: Ending the Confusion
The International Yard and Pound Agreement of 1959, signed by the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa, established:
1 international yard = 0.9144 meters (exactly)
1 international foot = 0.3048 meters (exactly)
1 international square foot = 0.09290304 m² (exactly)
This unified the foot globally and aligned imperial units with the metric system through exact conversion factors.
Exception: The US survey foot (1200/3937 meters) remains in use for some land surveys to maintain consistency with historical surveys. This creates a US survey square foot slightly different from the international square foot—a distinction only relevant in precision surveying.
Persistence Despite Metrication (1960s-Present)
Throughout the 20th century, most countries adopted the metric system. However, square feet remain dominant in:
United States: Exclusively uses square feet for residential real estate. All home listings, construction documents, building codes, and HVAC calculations use ft². Metrication efforts failed in the 1970s.
United Kingdom: Officially metricated in 1995, requiring metric units in commerce. However, real estate continues to list properties in both square feet and square meters, with square feet often prominently displayed due to consumer preference and historical familiarity.
Canada: Officially metricated (square meters), but square footage remains common in real estate listings and construction, particularly in regions near the US border.
India, Pakistan, Bangladesh: Use square feet as the primary unit for real estate despite official metrication. Property advertisements overwhelmingly use sq ft.
Hong Kong, Singapore, Malaysia: Mixed systems. Hong Kong historically used square feet but increasingly shows square meters. Singapore mandates square meters but square feet remain understood.
The Real Estate Lock-In Effect
Square footage persists in real estate due to:
- Consumer familiarity: Buyers understand "2,000 sq ft" intuitively from years of exposure
- Historical data: Decades of comparable sales in square feet make valuation easier
- Industry resistance: Realtors, appraisers, and builders resist change due to retraining costs
- Building codes: US building codes specify minimum room sizes in square feet
- Property taxation: Tax assessments based on square footage in many jurisdictions
Common Uses and Applications: square kilometers vs square feet
Explore the typical applications for both Square Kilometer (metric) and Square Foot (imperial/US) to understand their common contexts.
Common Uses for square kilometers
The square kilometer is the international standard for measuring large-scale areas:
Geography and Cartography
The standard unit for stating land or surface area of countries, continents, large islands, administrative divisions (states, provinces), and major cities.
Geographic Applications:
- Country and territory sizes
- Continental land masses
- Island and archipelago areas
- Administrative boundaries
- Political divisions
- City and metropolitan areas
Why it's universal:
- Standardized for international comparison
- Used in atlases, maps, and geographic databases
- Required for official government statistics
- Essential for treaties and agreements
Convert for international comparisons
Demography
Essential for calculating population density, typically expressed as inhabitants per square kilometer (people/km²). This is the international standard for comparing population distribution.
Population Density Uses:
- Comparing urban vs rural population spread
- Planning infrastructure needs
- Resource allocation per capita
- Understanding settlement patterns
- Environmental impact assessment
Formula: Population Density = Total Population ÷ Area (km²)
Example: Japan has 333 people/km², while Canada has only 4 people/km²
Environmental Science
Measuring the extent of large ecosystems, national parks, conservation areas, watersheds, ice sheets, deforestation, and environmental impacts.
Environmental Applications:
- Forest monitoring: Amazon = 5.5 million km²
- Deforestation tracking: Loss measured in km²/year
- Protected areas: Park sizes, marine reserves
- Ice sheet coverage: Antarctic ice = 14 million km²
- Disaster areas: Flood extent, wildfire spread, oil spill coverage
- Habitat mapping: Species range and distribution
Climate Research:
- Sea ice extent (measured seasonally in km²)
- Glacier coverage changes
- Desert expansion/contraction
- Vegetation cover changes
Use our square kilometer converter for environmental calculations.
Urban Planning and Land Management
Quantifying large zones, districts, or total city area in regional planning, metropolitan development, and land use management.
Urban Applications:
- City boundaries and total area
- Metropolitan area extent
- Urban sprawl measurement
- Zoning district sizes
- Green space allocation
- Development planning
Regional Planning:
- Transportation networks
- Utility coverage areas
- Emergency service zones
- School district boundaries
- Municipal service areas
Geology and Planetary Science
Measuring the surface area of large geological formations or the surface areas of planets, moons, and asteroids.
Geological Features:
- Volcanic fields
- Impact craters
- Lava flow areas
- Tectonic plate coverage
- Mineral deposit areas
Planetary Measurements:
- Earth surface: 510 million km²
- Mars surface: 145 million km²
- Moon surface: 38 million km²
- Crater sizes on planets/moons
Military and Logistics
Defining large operational areas, zones, and territories for defense, operations planning, and strategic analysis.
Military Applications:
- Theater of operations
- Exclusion zones
- Patrol areas
- Training grounds
- Strategic territories
Real Estate and Property (Large Scale)
While hectares or acres are more common for individual properties, square kilometers are used for:
- Very large land holdings (ranches, estates)
- Land development projects
- Agricultural regions
- Forestry concessions
- Mining leases
Example: A large cattle ranch might be 100-500 km²
Agriculture (Regional Scale)
While individual farms use hectares, agricultural regions and total crop areas are measured in square kilometers:
- Total agricultural land per country
- Grain belt regions
- Wine regions
- Crop suitability zones
- Irrigation coverage areas
Example: Corn Belt in USA covers approximately 500,000 km²
International Comparisons
Essential for comparing regions, countries, and geographic features across borders and continents.
Comparison Uses:
- "Country X is about the size of State Y"
- "This forest is larger than Country Z"
- "The disaster area equals 10 times the size of City A"
Common Comparisons:
- Singapore (728 km²) is smaller than New York City (1,214 km²)
- United Kingdom (242,495 km²) is about the same size as Oregon (254,799 km²)
- Australia (7.7 million km²) is about the same size as the contiguous USA (8.1 million km²)
Convert for comparisons: km² to square miles | km² to acres
When to Use square feet
1. Real Estate Listings and Sales
Square footage is the primary metric for home valuation in the US, Canada, and UK. Property listings always specify total square footage, often breaking down:
- Total living area (heated/cooled space)
- Bedroom sizes (sq ft per room)
- Basement area (finished vs. unfinished)
- Garage (often listed separately)
Price per square foot is the key metric for comparable sales analysis:
- National US average (2025): $150-200/sq ft for new construction
- Urban markets (San Francisco, NYC): $400-1,000+/sq ft
- Suburban markets: $100-250/sq ft
- Rural markets: $80-150/sq ft
Example: A 2,000 sq ft home listed at $400,000 = $200/sq ft
2. Construction and Architecture
Blueprints, floor plans, and construction documents use square feet for:
- Floor area calculations (required for building permits)
- Material estimates (flooring, drywall, roofing in sq ft)
- Cost estimating (construction cost per sq ft)
- Zoning compliance (maximum floor area ratio, minimum room sizes)
Construction costs (2025 US averages):
- Budget home: $100-150/sq ft
- Standard home: $150-250/sq ft
- Custom home: $250-400/sq ft
- Luxury home: $400-800+/sq ft
3. Flooring and Home Improvement
Flooring materials (carpet, tile, hardwood, laminate) are purchased by the square foot. Homeowners measure room dimensions to calculate total square footage needed, adding 10-15% for waste.
Calculation example:
- Living room: 15' × 18' = 270 sq ft
- Add 10% waste: 270 × 1.10 = 297 sq ft
- Order 300 sq ft of flooring
Paint coverage: One gallon covers ~350-400 sq ft per coat (varies by surface texture). Calculate wall square footage: (Perimeter × Height) - (window/door areas).
4. HVAC System Design
Heating and cooling systems are sized in BTUs or tons, calculated based on square footage of conditioned space. HVAC contractors use Manual J load calculations that account for:
- Square footage (primary factor)
- Insulation levels (R-values)
- Window area and efficiency
- Climate zone
- Air infiltration rates
Rule of thumb: Oversimplified (1 ton/400 sq ft), but professional calculations adjust for specifics.
5. Property Taxation and Assessment
Many jurisdictions calculate property taxes partially based on square footage. Assessors measure "finished living area" to determine assessed value.
Example: A county might assess homes at $150/sq ft, so a 2,500 sq ft home has an assessed value of $375,000, with property tax = assessed value × tax rate (e.g., $375,000 × 1.2% = $4,500/year).
6. Interior Design and Space Planning
Interior designers use square footage to:
- Determine appropriate furniture sizes for rooms
- Calculate occupancy limits (building codes specify sq ft per person)
- Specify area rug sizes
- Plan layouts and circulation space
Furniture scale guidelines:
- Small bedroom (100 sq ft): Twin/full bed, nightstand, small dresser
- Medium bedroom (150 sq ft): Queen bed, two nightstands, dresser, chair
- Large bedroom (250 sq ft): King bed, full furniture set, seating area
Additional Unit Information
About Square Kilometer (km²)
How many square meters are in one square kilometer?
There are exactly 1,000,000 square meters (m²) in one square kilometer.
Calculation: 1 km² = 1,000 m × 1,000 m = 1,000,000 m²
Conversion:
- 1 km² = 1,000,000 m²
- 0.1 km² = 100,000 m²
- 0.01 km² = 10,000 m²
- Example: 2.5 km² = 2,500,000 m²
Use our square kilometer to square meter converter for instant conversions.
How many hectares are in one square kilometer?
There are exactly 100 hectares (ha) in one square kilometer.
Why: 1 km² = 1,000,000 m² and 1 ha = 10,000 m², therefore: 1 km² = 1,000,000 m² ÷ 10,000 m²/ha = 100 ha
Conversion examples:
- 1 km² = 100 hectares
- 10 km² = 1,000 hectares
- 0.5 km² = 50 hectares
- 2.5 km² = 250 hectares
When to use which:
- Hectares: Farms, parks, smaller land areas (1-1,000 ha)
- Square kilometers: Cities, regions, countries (0.1+ km²)
Convert between them: km² to hectares | Hectares to km²
How do you convert square kilometers to square miles?
To convert square kilometers to square miles, multiply the area in square kilometers by approximately 0.386102.
Conversion formula: Area [mi²] ≈ Area [km²] × 0.386102
Examples:
- 1 km² ≈ 0.386 mi²
- 10 km² ≈ 3.86 mi²
- 100 km² ≈ 38.6 mi²
- 1,000 km² ≈ 386 mi²
Reverse conversion (square miles to square kilometers):
- Multiply by approximately 2.58999
- 1 mi² ≈ 2.59 km²
Why this factor?:
- 1 km = 0.621371 miles
- 1 km² = (0.621371)² = 0.386102 mi²
Use our km² to mi² converter for accurate conversions without manual calculation.
Is the square kilometer an official SI unit?
Technically, the official SI derived unit for area is the square meter (m²).
However, the square kilometer (km²) is a standard and fully accepted multiple within the metric system and for use alongside SI units.
Why it's accepted:
- Formed by combining an SI prefix (kilo-) with the SI base unit (meter) raised to the power of two
- Follows SI conventions and decimal scaling
- Listed in SI documentation as a "unit accepted for use with SI"
- Used universally in scientific, technical, and official applications
In practice:
- m² is the "base" SI unit for area
- km² is the practical unit for large areas
- Both are fully part of the international metric system
What is the difference between a kilometer and a square kilometer?
Kilometer (km) is a unit of length or distance (one dimension). Square kilometer (km²) is a unit of area (two dimensions).
The difference:
Kilometer (km) - 1D:
- Measures distance, length, height
- Examples: Road length, height of mountain, distance between cities
- Linear measurement
Square Kilometer (km²) - 2D:
- Measures area, surface
- Examples: Size of a country, area of a lake, extent of a forest
- Represents a square with sides of one kilometer each
Key distinction:
- 10 km might be the distance from point A to point B
- 10 km² might be the area of a small town
Analogy:
- Kilometer is like measuring the perimeter of a fence
- Square kilometer is like measuring the area inside the fence
How big is 1 square kilometer visually?
1 square kilometer (km²) is a square with sides exactly 1 kilometer (1,000 meters) long.
Visual comparisons:
- 100 American football fields (including end zones)
- About 150 soccer/football fields
- 0.39 square miles (just over 1/3 of a square mile)
- 247 acres (almost 250 acres)
- A 10-minute walk around the perimeter (4 km)
In city terms:
- Small to medium neighborhood
- 2-4 city blocks (in large US cities)
- Area you could see from a tall building
- Walking distance of 15-20 minutes to cross
In rural terms:
- Large farm
- Small village area
- Several hundred house lots
Perspective:
- Central Park (NYC): 3.41 km²
- Vatican City: 0.44 km²
- Monaco: 2.02 km²
How to visualize: Imagine walking 1 km north, then 1 km east, then 1 km south, then 1 km west back to start - the area inside is 1 km².
What is 100 km² equivalent to?
100 square kilometers = 38.6 square miles = 10,000 hectares = 24,710 acres
City examples (approximately 100 km² or close):
- Paris (city proper): 105 km²
- Washington, D.C.: 177 km²
- Boston: 232 km²
- San Francisco: 121 km²
- Miami: 143 km²
- Manhattan: 59 km² (about 60% of 100 km²)
Country examples (small island nations):
- Maldives: 300 km² (about 3 times)
- Grenada: 344 km² (about 3.5 times)
- Saint Vincent: 389 km² (about 4 times)
Natural features:
- Medium-sized lake
- Large national park or nature reserve
- Small island
- Significant forest area
Population examples:
- At urban density (5,000 people/km²): 500,000 people
- At suburban density (1,000 people/km²): 100,000 people
- At rural density (50 people/km²): 5,000 people
Practical understanding:
- Medium-sized city or large town
- Area you could drive across in 15-30 minutes
- Typical county in smaller US states
Convert 100 km²: to square miles | to hectares
How do you calculate the area in square kilometers?
Basic formula for rectangles: Area (km²) = Length (km) × Width (km)
Step-by-step process:
1. Measure dimensions:
- Measure length and width in kilometers
- If measured in meters, divide by 1,000 to get kilometers
- If measured in miles, multiply by 1.609 to get kilometers
2. Calculate:
- Multiply length by width
- Result is in square kilometers
Examples:
Example 1 - Simple rectangle:
- Length: 5 km
- Width: 3 km
- Area = 5 km × 3 km = 15 km²
Example 2 - From meters:
- Length: 2,500 meters = 2.5 km
- Width: 4,000 meters = 4 km
- Area = 2.5 km × 4 km = 10 km²
Example 3 - From miles:
- Length: 6 miles = 9.66 km
- Width: 4 miles = 6.44 km
- Area = 9.66 km × 6.44 km ≈ 62.2 km²
For complex shapes:
Circle:
- Area = π × radius²
- If radius = 5 km: Area = 3.14159 × 5² ≈ 78.5 km²
Irregular shapes:
- Divide into triangles/rectangles
- Calculate each section
- Add all sections together
- Or use GIS/mapping software
Using GPS coordinates:
- Use online area calculators
- Import coordinates into GIS software
- Software calculates irregular polygons automatically
Verification:
- Use our area converter to check your calculations
- Convert to other units to verify makes sense
What countries are about 1,000 km²?
Countries close to 1,000 km² (between 500-1,500 km²):
Very close to 1,000 km²:
- Hong Kong: 1,104 km²
- Samoa: 2,842 km²
- Luxembourg: 2,586 km²
- Mauritius: 2,040 km²
Between 500-1,000 km²:
- Singapore: 728 km²
- Bahrain: 778 km²
- Kiribati: 811 km²
- Tonga: 747 km²
- Federated States of Micronesia: 702 km²
- Saint Lucia: 617 km²
- Andorra: 468 km²
Between 1,000-1,500 km²:
- Cape Verde: 4,033 km²
- Trinidad and Tobago: 5,131 km²
- Comoros: 1,862 km²
- São Tomé and Príncipe: 964 km²
For comparison:
- 1,000 km² = 386 square miles
- About the size of Hong Kong or 10x the size of Paris
- Smaller than most US counties
- Medium-sized metropolitan area
Interesting fact: Only about 30 countries are smaller than 1,000 km², mostly island nations and microstates.
How many acres is a square kilometer?
1 square kilometer = 247.105 acres (commonly rounded to 247 acres)
Conversion formula: Acres = km² × 247.105
Examples:
- 1 km² = 247 acres
- 5 km² = 1,235 acres
- 10 km² = 2,471 acres
- 100 km² = 24,710 acres
- 0.1 km² = 24.7 acres
Reverse conversion (acres to km²):
- 1 acre = 0.00405 km²
- 100 acres = 0.405 km²
- 1,000 acres = 4.05 km²
- 10,000 acres = 40.5 km²
Perspective:
- A square kilometer is about 247 football fields
- A large farm might be 200-400 acres (0.8-1.6 km²)
- A golf course is typically 50-80 acres (0.2-0.3 km²)
When to use which:
- Acres: US land parcels, farms, developments (< 1,000 acres)
- Square kilometers: Large regions, cities, countries (> 0.5 km²)
Use our converter: km² to acres | Acres to km²
How is square kilometers different from cubic kilometers?
Square Kilometers (km²) and Cubic Kilometers (km³) measure different things:
Square Kilometers (km²) - AREA (2D):
- Measures surface area
- Two-dimensional
- Example: Land area of a country, surface of a lake
- Unit: km × km = km²
Cubic Kilometers (km³) - VOLUME (3D):
- Measures volume or capacity
- Three-dimensional
- Example: Volume of water in a lake, ice in a glacier
- Unit: km × km × km = km³
Real-world examples:
Lake Michigan:
- Area (surface): 58,000 km²
- Volume (water): 4,920 km³
Amazon Rainforest:
- Area (coverage): 5,500,000 km²
- Volume (if measuring biomass in 3D): Would be km³
City:
- Area (footprint): Measured in km²
- Volume (including buildings/air): Could be km³ (rarely used)
Key differences:
| Feature | km² (Area) | km³ (Volume) | |---------|-----------|--------------| | Dimensions | 2D (length × width) | 3D (length × width × height) | | Measures | Surface area | Space/capacity | | Examples | Country size, lake surface | Water volume, ice volume | | Conversion | 1 km² = 1,000,000 m² | 1 km³ = 1,000,000,000 m³ |
Remember:
- km² = Flat surface measurement
- km³ = 3D space measurement
What is the area of the Earth in square kilometers?
Total Earth surface area: Approximately 510,000,000 km² (510 million km²)
Breakdown:
Water (Oceans and seas):
- Area: ~361,000,000 km² (361 million km²)
- Percentage: ~71% of Earth's surface
- All oceans, seas, lakes combined
Land:
- Area: ~149,000,000 km² (149 million km²)
- Percentage: ~29% of Earth's surface
- All continents and islands
Continents by area:
- Asia: 44,579,000 km²
- Africa: 30,370,000 km²
- North America: 24,709,000 km²
- South America: 17,840,000 km²
- Antarctica: 14,000,000 km² (varies with ice)
- Europe: 10,180,000 km²
- Australia/Oceania: 8,600,000 km²
Oceans by area:
- Pacific: 165,200,000 km²
- Atlantic: 106,460,000 km²
- Indian: 70,560,000 km²
- Southern: 20,327,000 km²
- Arctic: 14,060,000 km²
In other units:
- 510 million km² = 196.9 million mi²
- 510 million km² = 51 billion hectares
Interesting comparisons:
- Russia (largest country): 17 million km² = 3.3% of Earth's surface
- Pacific Ocean alone: 32% of Earth's surface
- All land combined: About the size of the Pacific Ocean + Atlantic Ocean
Note: These are approximate values; exact measurements vary slightly based on sea level, ice coverage, and measurement methodology.
About Square Foot (ft²)
How big is one square foot visually?
One square foot is a square measuring 12 inches (1 foot) on each side.
Common objects:
- Standard 12"×12" floor tile: Exactly 1 square foot
- Large pizza (14" diameter): About 1.07 sq ft (π×7²/144)
- Sheet of paper (8.5"×11"): 0.65 sq ft (93.5 in² ÷ 144)
- Laptop computer (typical 15"): ~0.7-0.9 sq ft
Hand estimation: A handspan (thumb to pinky) stretched out is roughly 9-10 inches, so imagine a square slightly larger than your handspan on each side.
How many square inches are in a square foot?
Exactly 144 square inches (in²) in one square foot.
Calculation: 1 foot = 12 inches, so 1 ft² = 12" × 12" = 144 in²
Examples:
- 1 ft² = 144 in²
- 2 ft² = 288 in²
- 0.5 ft² = 72 in²
- 10 ft² = 1,440 in²
Use case: Small materials (glass panes, small tiles) sold in square inches can be converted to square feet for larger projects.
How many square feet are in a square yard?
Exactly 9 square feet in one square yard.
Calculation: 1 yard = 3 feet, so 1 yd² = 3' × 3' = 9 ft²
Examples:
- 1 yd² = 9 ft²
- 10 yd² = 90 ft²
- 30 yd² = 270 ft²
- 100 yd² = 900 ft²
Carpet pricing: Carpet is often priced per square yard. To find total cost, divide room sq ft by 9 to get sq yd, then multiply by price per sq yd.
Example: 270 sq ft room ÷ 9 = 30 sq yd. At $25/sq yd, cost = $750.
How do I convert square feet to square meters?
Exact formula: m² = ft² × 0.09290304
Quick approximation: m² ≈ ft² ÷ 10.764 (or ft² ÷ 11 for rough estimates)
Examples:
- 100 ft² = 9.29 m²
- 500 ft² = 46.45 m²
- 1,000 ft² = 92.90 m²
- 2,000 ft² = 185.81 m²
- 3,500 ft² = 325.16 m²
Reverse (m² to ft²): ft² = m² × 10.7639
Memory aid: "Divide square feet by roughly 11 to get square meters" (slightly overestimates, but close)
How many square feet are in an acre?
Exactly 43,560 square feet in one acre.
Calculation: 1 acre = 1 furlong × 1 chain = 660' × 66' = 43,560 ft²
Common fractions:
- 1/4 acre = 10,890 ft²
- 1/2 acre = 21,780 ft²
- 3/4 acre = 32,670 ft²
- 1 acre = 43,560 ft²
Visualization: An acre is roughly 208.7' × 208.7' (a square), or 43,560 sq ft in any shape.
Typical lot: A 0.25-acre suburban lot (~11,000 sq ft) might be 100' × 110' or 90' × 122'.
What is the average size of a home in the US?
2025 statistics:
- Median new single-family home: 2,261 sq ft (210 m²)
- Average new single-family home: 2,480 sq ft (230 m²)
- Existing homes (median): ~2,000 sq ft (186 m²)
Historical trend:
- 1973: 1,660 sq ft median
- 1990: 1,905 sq ft median
- 2007 (peak): 2,521 sq ft median
- 2009 (recession low): 2,135 sq ft median
- 2025: 2,261 sq ft median
Regional variation:
- Western US: Larger (2,400-2,600 sq ft avg)
- Southern US: Larger (2,300-2,500 sq ft avg)
- Northeastern US: Smaller (1,800-2,200 sq ft avg)
- Urban areas: Significantly smaller (1,200-1,800 sq ft avg)
How much does flooring cost per square foot?
Flooring costs vary widely by material and installation complexity:
Materials only (2025 US averages):
- Carpet: $1-5/sq ft
- Laminate: $2-5/sq ft
- Vinyl plank (LVP): $2-7/sq ft
- Engineered hardwood: $3-10/sq ft
- Solid hardwood: $5-15/sq ft
- Tile (ceramic): $1-10/sq ft
- Tile (porcelain): $3-15/sq ft
- Natural stone: $5-30/sq ft
Installed (material + labor):
- Carpet: $3-8/sq ft
- Laminate: $5-10/sq ft
- LVP: $6-12/sq ft
- Engineered hardwood: $8-18/sq ft
- Solid hardwood: $12-25/sq ft
- Tile: $10-30/sq ft
Total cost example: 1,000 sq ft of mid-grade engineered hardwood at $12/sq ft installed = $12,000
How do I calculate the square footage of my home?
For a rectangular home:
- Measure length and width of each room in feet
- Multiply length × width for each room (= sq ft)
- Sum all rooms
Example:
- Living room: 15' × 18' = 270 sq ft
- Kitchen: 12' × 14' = 168 sq ft
- Bedroom 1: 12' × 12' = 144 sq ft
- Bedroom 2: 10' × 11' = 110 sq ft
- Bathroom: 8' × 9' = 72 sq ft
- Total: 764 sq ft
For irregular spaces:
- Divide into rectangles, measure each, sum areas
- Or use a laser measure/measuring wheel
- Or use smartphone apps (RoomScan, MagicPlan) that use AR
What to include:
- Include: Heated/cooled living space, closets, hallways
- Exclude: Garage (listed separately), unfinished basement, attics, open porches
- Gray area: Finished basements often listed separately as "finished basement sq ft"
Professional measurement: Appraisers follow ANSI standards (Z765-2021) for consistent measurement.
Is the square foot an SI unit?
No, the square foot is not part of the International System of Units (SI). It belongs to imperial and US customary systems.
The SI unit for area is the square meter (m²).
However, square feet remain legally accepted for commerce in the US and are widely used alongside square meters in the UK, Canada, India, and many Commonwealth nations despite official metrication.
International context: When publishing for international audiences or scientific work, convert square feet to square meters (×0.0929).
Why are homes measured in square feet instead of square meters in the US?
Historical inertia: The US never fully metricated. Square footage has been standard in US real estate and construction for over a century.
Consumer familiarity: Americans intuitively understand home sizes in square feet. "2,000 square feet" is meaningful; "185 square meters" requires mental conversion.
Industry entrenchment: Building codes, zoning laws, construction standards, and appraisal methods all use square feet. Switching would require massive regulatory updates and retraining.
Resistance to change: Attempts to metricate the US in the 1970s (Metric Conversion Act of 1975) failed due to public and industry opposition.
Network effects: Since all comparable sales data is in square feet, realtors and buyers rely on it for valuation. Switching unilaterally would confuse comparisons.
Result: Square feet remain universal in US real estate, construction, and home improvement despite metric adoption in science, medicine, and manufacturing.
How many square feet do I need per person in a home?
Rough guidelines (varies by lifestyle, culture, family composition):
Minimum livable:
- 200-300 sq ft per person: Tight but functional (studio/small apartment)
- 400-600 sq ft per person: Comfortable (typical family home)
- 800-1,000+ sq ft per person: Spacious (luxury homes)
Examples:
- Single person: 400-800 sq ft (studio to 1-bedroom)
- Couple: 800-1,200 sq ft (1-2 bedrooms)
- Family of 3: 1,200-1,800 sq ft (2-3 bedrooms)
- Family of 4: 1,600-2,500 sq ft (3-4 bedrooms)
- Family of 5+: 2,000-3,500+ sq ft (4-5 bedrooms)
International comparison:
- US average: ~600-700 sq ft per person (2025)
- UK average: ~350-400 sq ft per person
- European Union: ~400-500 sq ft per person
- Japan: ~300-350 sq ft per person
- Hong Kong: ~150-200 sq ft per person (very dense)
Conversion Table: Square Kilometer to Square Foot
| Square Kilometer (km²) | Square Foot (ft²) |
|---|---|
| 0.5 | 5,381,955.208 |
| 1 | 10,763,910.417 |
| 1.5 | 16,145,865.625 |
| 2 | 21,527,820.833 |
| 5 | 53,819,552.084 |
| 10 | 107,639,104.167 |
| 25 | 269,097,760.418 |
| 50 | 538,195,520.836 |
| 100 | 1,076,391,041.671 |
| 250 | 2,690,977,604.177 |
| 500 | 5,381,955,208.355 |
| 1,000 | 10,763,910,416.71 |
People Also Ask
How do I convert Square Kilometer to Square Foot?
To convert Square Kilometer to Square Foot, enter the value in Square Kilometer in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our area converter page to convert between other units in this category.
Learn more →What is the conversion factor from Square Kilometer to Square Foot?
The conversion factor depends on the specific relationship between Square Kilometer and Square Foot. You can find the exact conversion formula and factor on this page. Our calculator handles all calculations automatically. See the conversion table above for common values.
Can I convert Square Foot back to Square Kilometer?
Yes! You can easily convert Square Foot back to Square Kilometer by using the swap button (⇌) in the calculator above, or by visiting our Square Foot to Square Kilometer converter page. You can also explore other area conversions on our category page.
Learn more →What are common uses for Square Kilometer and Square Foot?
Square Kilometer and Square Foot are both standard units used in area measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our area converter for more conversion options.
For more area conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
All Area Conversions
Other Area Units and Conversions
Explore other area units and their conversion options:
- Square Meter (m²) • Square Kilometer to Square Meter
- Square Centimeter (cm²) • Square Kilometer to Square Centimeter
- Square Millimeter (mm²) • Square Kilometer to Square Millimeter
- Square Inch (in²) • Square Kilometer to Square Inch
- Square Yard (yd²) • Square Kilometer to Square Yard
- Square Mile (mi²) • Square Kilometer to Square Mile
- Acre (acre) • Square Kilometer to Acre
- Hectare (ha) • Square Kilometer to Hectare
Verified Against Authority Standards
All conversion formulas have been verified against international standards and authoritative sources to ensure maximum accuracy and reliability.
National Institute of Standards and Technology — Standards for area measurements
Last verified: December 3, 2025