Acre to Square Millimeter Conversion Calculator: Free Online Tool
Convert acres to square millimeters with our free online area converter.
Acre to Square Millimeter Calculator
How to Use the Calculator:
- Enter the value you want to convert in the 'From' field (Acre).
- The converted value in Square Millimeter 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 Acre to Square Millimeter
Converting Acre to Square Millimeter involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Acre = 4046856000 square millimetersExample Calculation:
Convert 10 acres: 10 × 4046856000 = 40468560000 square millimeters
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.
What is a Acre and a Square Millimeter?
The acre (symbol: ac) is a unit of land area used in the imperial and US customary systems. It is traditionally defined as the area of one chain by one furlong (66 by 660 feet). This is exactly equal to:
- 10 square chains
- 1/640 of a square mile
- 4,840 square yards
- 43,560 square feet
- Approximately 4,046.856 square meters (m²)
- Approximately 0.4047 hectares (ha)
While derived from traditional farming practices, its size is now legally defined based on the international yard.
The Square Millimeter (symbol: mm² or sq mm) is a unit of area in the International System of Units (SI). It represents the area of a square whose sides measure exactly one millimeter (mm) in length.
Key relationships:
- 1 mm² = 1 millimeter × 1 millimeter
- 1 meter (m) = 1,000 millimeters (mm)
- 1 square meter (m²) = (1,000 mm) × (1,000 mm) = 1,000,000 mm²
- 1 square centimeter (cm²) = (10 mm) × (10 mm) = 100 mm² (or 1 mm² = 0.01 cm²)
In terms of imperial/US customary units:
- 1 inch = 25.4 mm exactly
- 1 square inch (in²) = (25.4 mm)² = 645.16 mm²
- Therefore, 1 mm² ≈ 0.00155 square inches (in²)
Note: The Acre is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Square Millimeter belongs to the metric (SI) system.
History of the Acre and Square Millimeter
- Origin: The word "acre" derives from the Old English word æcer (originally meaning "open field"), cognate with German Acker and Latin ager. It traditionally represented the amount of land that could be ploughed by one man with one yoke of oxen in one day. This practical definition naturally led to considerable variation in its size depending on the land quality and local customs.
- Medieval Variations: Throughout the Middle Ages in England, the acre's size varied. Different regions used "customary acres" based on local practices, often related to the quality of the land or the length of a standard furrow (furlong).
- Standardization (Gunter's Chain): The standardization of the acre is closely linked to the invention of Gunter's chain in 1620. This measuring chain, 66 feet long (divided into 100 links), became a standard survey tool. The traditional definition of an acre as a strip of land one furlong (10 chains or 660 feet) long and one chain (66 feet) wide was easily measured using the chain. This area is precisely 10 square chains.
- Statutory Acre: In England and Wales, the Weights and Measures Act of 1878 formalized the "statutory acre" based on the imperial yard, solidifying the definition as 4,840 square yards (or 43,560 square feet). This is the acre commonly used today in the UK, US, and Commonwealth countries.
- Metrication: Although many countries using the acre have largely adopted the metric system for other measurements, the acre persists strongly in land transactions and agriculture due to historical precedent and cultural familiarity. The hectare (10,000 m²) is the more common metric unit for land.
- Origin (Millimeter): The square millimeter is derived directly from the millimeter, which itself is derived from the meter, the base unit of length in the metric system established during the French Revolution. The prefix "milli-" denotes one-thousandth (1/1000).
- Metric System Coherence: The square millimeter arose naturally within the decimal-based metric system as the appropriate unit for measuring very small areas, by squaring the millimeter length unit.
- SI Standardisation: With the formal establishment of the International System of Units (SI) in 1960, the square meter (m²) was confirmed as the derived unit for area. The square millimeter, formed using an SI prefix (milli-) and the base unit (meter) squared, became a standard SI unit for area, suitable for fine-scale measurements.
- Technological Need: The widespread use of the square millimeter grew significantly with advancements in science and technology requiring precise measurement of very small objects and features, such as in microscopy, electronics, and precision engineering.
Common Uses for acres and square millimeters
Explore the typical applications for both Acre (imperial/US) and Square Millimeter (metric) to understand their common contexts.
Common Uses for acres
The acre remains a primary unit for land measurement in several countries, particularly within specific sectors:
- Real Estate (US, UK, Commonwealth): Standard unit for describing the size of land parcels in property listings, deeds, and surveys, especially for residential lots larger than typical city plots, rural properties, and undeveloped land.
- Agriculture: Widely used by farmers to measure field sizes, calculate crop yields, allocate resources (like fertilizer or seeds), and comply with agricultural regulations.
- Land Management and Planning: Used in zoning regulations, environmental assessments, and land development projects to specify area requirements or limitations.
- Historical Documents: Understanding the acre is crucial for interpreting historical land records, surveys, and deeds.
- Informal Comparisons: Often used informally to help visualize the size of large areas, even where metric units are officially standard.
Common Uses for square millimeters
The square millimeter is used for measuring extremely small areas, primarily in technical and scientific contexts:
- Engineering and Manufacturing: Specifying cross-sectional areas of fine wires, optical fibers, and small mechanical components; defining surface areas of micro-electromechanical systems (MEMS); measuring surface roughness features.
- Material Science: Quantifying the area of microscopic structures like crystal grains, pores, or defects in materials under microscopic analysis; measuring the area of test indentations (e.g., in hardness testing).
- Electronics: Defining the area of contact pads, traces, vias, and components on printed circuit boards (PCBs) and integrated circuits (ICs).
- Optics: Measuring the effective area of small apertures, detector pixels, laser beam cross-sections, or optical fiber cores.
- Medicine and Biology: Measuring the cross-sectional area of fine capillaries, nerve fibers, or cells under a microscope; quantifying the area of small lesions or tissue samples.
- Physics: Used in calculations involving small surfaces, pressures on small areas, or flux densities.
It is generally far too small for everyday measurements like room sizes or land areas.
Frequently Asked Questions
Questions About Acre (acre)
How big is an acre visually?
An acre is 43,560 square feet. While it can be any shape, a square acre would be about 208.71 feet on each side. A common visual comparison is an American football field: one acre is about 90.75% of the total area of a standard American football field (which is 120 yards long by 53.33 yards wide, or 57,600 sq ft including end zones). Excluding the end zones (100 yards by 53.33 yards, or 48,000 sq ft), an acre is about 90.75% of the playing field area.
How many square feet are in an acre?
There are exactly 43,560 square feet in one acre. This definition (1 furlong × 1 chain = 660 ft × 66 ft) is precise.
How many square yards are in an acre?
There are exactly 4,840 square yards in one acre (since 1 yard = 3 feet, 1 square yard = 9 square feet; 43,560 / 9 = 4,840).
How many acres are in a square mile?
There are exactly 640 acres in one square mile.
How many acres are in a hectare?
One hectare is equal to 10,000 square meters. Since one acre is approximately 4,046.856 square meters, one hectare contains approximately 2.471 acres (10,000 / 4046.856 ≈ 2.471). Conversely, one acre is approximately 0.4047 hectares.
Is the acre an SI unit?
No, the acre is not part of the International System of Units (SI). It belongs to the imperial and US customary systems. The SI unit for area is the square meter (m²). For land measurement, the hectare (ha), equal to 10,000 m², is commonly used in metric contexts and is accepted for use with SI.
About Square Millimeter (mm²)
How many square millimeters are in a square centimeter?
There are exactly 100 square millimeters (mm²) in one square centimeter (cm²). This is because 1 cm = 10 mm, so 1 cm² = (10 mm) × (10 mm) = 100 mm².
How many square millimeters are in a square meter?
There are exactly 1,000,000 square millimeters (mm²) in one square meter (m²). This is because 1 m = 1000 mm, so 1 m² = (1000 mm) × (1000 mm) = 1,000,000 mm².
How do you convert square millimeters to square inches?
To convert square millimeters to square inches, multiply the area in square millimeters by approximately 0.00155 (or divide by 645.16).
- Conversion formula: Area [in²] ≈ Area [mm²] × 0.00155
- Example: 500 mm² ≈ 500 × 0.00155 in² ≈ 0.775 in²
Is the square millimeter an official SI unit?
Yes, the square millimeter (mm²) is an SI unit of area. It is derived from the SI base unit of length, the meter, using the standard SI prefix "milli-". While the square meter is the fundamental SI unit of area, square millimeters are standard for measuring very small areas.
Is mm² commonly used for paper sizes?
No. Standard paper sizes (like A4, Letter) are typically defined using millimeters (mm) for their dimensions (length and width), but their area is usually expressed in square meters (m²) or square centimeters (cm²) if needed, not typically square millimeters.
Conversion Table: Acre to Square Millimeter
| Acre (acre) | Square Millimeter (mm²) |
|---|---|
| 1 | 4,046,856,422.4 |
| 5 | 20,234,282,112 |
| 10 | 40,468,564,224 |
| 25 | 101,171,410,560 |
| 50 | 202,342,821,120 |
| 100 | 404,685,642,240 |
| 500 | 2,023,428,211,200 |
| 1,000 | 4,046,856,422,400 |