Milligram to Kilogram Converter
Convert milligrams to kilograms with our free online weight converter.
Quick Answer
1 Milligram = 0.000001 kilograms
Formula: Milligram × conversion factor = Kilogram
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.
Milligram to Kilogram Calculator
How to Use the Milligram to Kilogram Calculator:
- Enter the value you want to convert in the 'From' field (Milligram).
- The converted value in Kilogram will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Weight category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Milligram to Kilogram: Step-by-Step Guide
Converting Milligram to Kilogram involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Milligram = 0.000001 kilogramsExample Calculation:
Convert 5 milligrams: 5 × 0.000001 = 0.000005 kilograms
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 weight units?
View all Weight conversions →What is a Milligram and a Kilogram?
The milligram (mg) is a unit of mass in the metric system equal to one-thousandth of a gram (1/1,000 g) or one-millionth of a kilogram (1/1,000,000 kg). It represents an extremely small quantity of mass, making it the preferred unit for measuring precise amounts of medications, nutrients, chemicals, and other substances where accuracy is paramount.
The milligram is part of the International System of Units (SI) and serves as a critical measurement standard in medicine, pharmacology, chemistry, nutrition science, and precision manufacturing. Its small scale allows for expressing tiny quantities without resorting to decimal fractions of grams, providing clarity and reducing the risk of measurement errors that could have serious consequences in medical and scientific applications.
The kilogram (symbol: kg) is the base unit of mass in the International System of Units (SI). It is one of the seven SI base units and forms the foundation for measuring mass and weight in the metric system.
Modern Definition (2019): The kilogram is defined by fixing the numerical value of the Planck constant (h) to be exactly 6.62607015×10⁻³⁴ joule-seconds (J⋅s). This definition, adopted on May 20, 2019 (World Metrology Day), replaced the previous definition based on a physical artifact.
Key relationships:
- 1 kilogram = 1,000 grams (g)
- 1 kilogram = 1,000,000 milligrams (mg)
- 1 kilogram = 0.001 metric tons (tonnes)
- 1,000 kilograms = 1 metric ton
In terms of imperial/US customary units:
- 1 kilogram ≈ 2.20462 pounds (lb) - Convert kg to lb
- 1 kilogram ≈ 35.274 ounces (oz) - Convert kg to oz
- 1 kilogram ≈ 0.157 stones (st) - Convert kg to stones
Visual perspective (how heavy is it?):
- 1 kg ≈ Liter bottle of water
- 1 kg ≈ Small laptop or tablet
- 1 kg ≈ Bag of sugar
- 1 kg ≈ Two pineapples
- 5 kg ≈ Newborn baby
- 10 kg ≈ Small dog or cat
Important distinction: While "mass" and "weight" are scientifically different (mass is the amount of matter, weight is gravitational force), in everyday usage, kilograms measure what we commonly call "weight."
Convert between weight units: kilogram converter
Note: The Milligram is part of the metric (SI) system, primarily used globally in science and trade. The Kilogram belongs to the metric (SI) system.
History of the Milligram and Kilogram
The milligram emerged as a practical subdivision of the gram when the metric system was formalized in France in the late 18th century. While the kilogram was established as the base unit of mass in 1795, scientists and physicians quickly recognized the need for much smaller units to measure chemicals, medicines, and biological samples.
The term "milligram" combines the Latin prefix "milli-" (meaning one-thousandth) with "gram," creating a logical decimal relationship that simplified calculations and conversions. This standardization was revolutionary—before the metric system, apothecaries used confusing units like grains, scruples, and drams, which varied by region and led to dangerous medication errors.
The importance of the milligram grew dramatically during the 19th century as pharmaceutical science advanced. The ability to precisely measure active ingredients in medications became critical for patient safety. By the early 20th century, the milligram had become the global standard for drug dosing, appearing on prescription labels, medication packaging, and medical literature worldwide.
The 1960 formalization of the International System of Units (SI) cemented the milligram's status as an official metric unit, though it's technically a submultiple of the kilogram rather than a base unit itself. Today, the milligram remains indispensable in healthcare, with virtually every pharmaceutical product worldwide labeled in milligrams.
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French Revolution Origins (1795): During the development of the metric system, French scientists defined the "grave" (later renamed kilogram) as the mass of one cubic decimeter (liter) of pure water at 4°C (its maximum density). This provided a definition based on nature rather than arbitrary standards.
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Kilogram des Archives (1799): The first physical standard was created - a platinum cylinder kept in the French National Archives in Paris. This "Kilogram of the Archives" served as France's official kilogram standard.
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Treaty of the Metre (1875): Seventeen nations signed this international treaty, establishing global cooperation on measurement standards. This set the stage for creating an international kilogram prototype.
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International Prototype Kilogram - Le Grand K (1889): A precisely machined platinum-iridium (90% platinum, 10% iridium) cylinder was created and designated as the international standard. This cylinder, known as "Le Grand K" or the IPK, was:
- 39 millimeters in both height and diameter
- Stored under three nested bell jars at the BIPM in Sèvres, France
- The only SI unit still defined by a physical artifact (until 2019)
- Accessed only rarely for calibration purposes
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The Problem with Le Grand K: Over time, scientists discovered that the IPK's mass was changing relative to its copies - by approximately 50 micrograms over a century. This was problematic because:
- The kilogram was drifting from its official definition
- No way to verify if the prototype was gaining or losing mass
- Physical objects can be damaged, contaminated, or lost
- Limited access meant difficult calibrations worldwide
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Search for a New Definition (1990s-2010s): Scientists developed two approaches:
- Kibble Balance (formerly watt balance): Relates mass to electromagnetic force and the Planck constant
- Avogadro Project: Count atoms in a silicon sphere to define the kilogram
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2019 Redefinition: On May 20, 2019 (World Metrology Day), the kilogram definition changed:
- Old: Mass of the International Prototype Kilogram
- New: Defined by fixing the Planck constant at exactly 6.62607015×10⁻³⁴ J⋅s
- This allows any properly equipped laboratory to reproduce the kilogram
- No longer depends on a physical object that could change or be damaged
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Why the Planck Constant?: This quantum mechanical constant relates energy to frequency and appears in fundamental physics equations. By fixing its value, mass can be measured using electromagnetic force through a Kibble balance.
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Global Impact: The kilogram is used by virtually every country worldwide. Even the United States, which uses pounds in daily life, uses kilograms extensively in:
- Scientific research
- International trade
- Medical dosing
- Manufacturing
- Athletics and sports
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Historical Significance: The 2019 redefinition was the culmination of over a century of metrological advancement, representing humanity's shift from physical artifacts to universal physical constants.
Common Uses and Applications: milligrams vs kilograms
Explore the typical applications for both Milligram (metric) and Kilogram (metric) to understand their common contexts.
Common Uses for milligrams
The milligram is essential across multiple fields:
Pharmaceuticals & Medicine:
- Prescription medication dosing and labeling
- Over-the-counter drug formulations
- Injectable medication concentrations (mg/mL)
- Pediatric dosing (often calculated as mg per kg of body weight)
- Hormone replacement therapy dosing
Nutrition & Food Science:
- Vitamin and mineral content on nutrition labels
- Dietary supplement formulations
- Sodium, cholesterol, and nutrient tracking
- Food additive regulations and limits
- Daily recommended intake guidelines
Scientific Research:
- Chemical synthesis and reagent measurement
- Biological sample preparation
- Environmental testing (pollutants, contaminants)
- Pharmaceutical research and development
- Quality control testing
Analytical Chemistry:
- Trace element analysis
- Drug testing and toxicology
- Water quality testing
- Soil sample analysis
- Forensic investigations
Precision Manufacturing:
- Microelectronics component specifications
- Fine powder measurements
- Catalyst preparation
- Cosmetics formulation
- Flavoring and fragrance compounds
When to Use kilograms
The kilogram is the universal standard for mass measurement across virtually all applications worldwide:
Science and Research
The fundamental unit for mass in all scientific disciplines. Essential for chemistry, physics, biology, medicine, and engineering research conducted globally.
Scientific Applications:
- Chemistry: Measuring reactants, products, and samples
- Physics: Mass calculations in mechanics and dynamics
- Biology: Specimen weights, culture media
- Medicine: Drug dosing, patient measurements
- Materials science: Sample preparation and analysis
- Environmental science: Pollution measurements, soil samples
Why kilograms in science:
- SI base unit (international standard)
- Decimal-based for easy calculations
- Defined by fundamental constant (Planck constant)
- Required for publication in scientific journals
- Universal reproducibility in any laboratory
Convert for scientific work: kilograms to other units
Healthcare and Medicine
Standard for patient weight, drug dosing, and medical calculations in hospitals and clinics worldwide. Critical for accurate treatment.
Medical uses:
- Patient weight: Baseline health measurement
- Drug dosing: Many medications dosed per kg body weight
- Pediatric care: Growth charts in kg and cm
- BMI calculation: Weight (kg) ÷ height² (m)
- Fluid management: IV fluids calculated by body weight
- Nutritional assessment: Protein needs, calorie requirements
- Medical research: Study participant measurements
Dosing examples:
- Pediatric antibiotics: 10-15 mg per kg body weight
- Anesthesia: Calculated per kg
- Chemotherapy: Often dosed per kg or body surface area
- Emergency medications: Weight-based dosing critical
Why critical in medicine:
- Precision prevents overdosing or underdosing
- International medical protocols use kg
- Pediatric safety depends on accurate weights
- Research requires standardized measurements
Food Industry and Nutrition
Standard unit for food packaging, recipes, nutritional labels, and commercial food sales in metric countries and international trade.
Food industry uses:
- Packaging labels: "Net weight: 1 kg"
- Commercial sales: Produce sold per kg
- Nutritional information: Values per 100g or serving
- Recipe scaling: Professional cooking in kg
- Food safety: Portion control, serving sizes
- Import/export: International food trade
- Restaurant supplies: Ingredients ordered in kg
Retail examples:
- Fruits and vegetables: Priced per kg
- Meat and fish: Sold by kg or portion
- Bulk foods: Rice, flour, nuts sold in kg bags
- Deli counters: Sliced meats weighed in kg
Shipping and Logistics
International standard for package weight, freight calculations, and postal rates. Essential for global commerce and transportation.
Shipping applications:
- Package weight limits: Carriers specify max kg
- Freight charges: Calculated per kg or dimensional weight
- Postal rates: Tiered by kg (0-2 kg, 2-5 kg, etc.)
- Air cargo: Charged per kg
- Container shipping: Weight limits in kg
- Customs declarations: Product weights in kg
- Warehouse inventory: Stock measured in kg
Standard limits:
- Small parcel: Up to 2 kg
- Standard parcel: 2-20 kg
- Heavy parcel: 20-30 kg
- Freight: 30+ kg
Why kg in shipping:
- International standard (UPU uses kg)
- Simplifies cross-border shipping
- Aviation industry uses kg
- Maritime shipping uses metric tons (1,000 kg)
Athletics and Sports
Standard for athlete weight classes, equipment specifications, and performance measurements in international competition.
Weight classes (examples):
- Boxing: Flyweight (< 51 kg), Welterweight (< 69 kg), Heavyweight (> 91 kg)
- Wrestling: Multiple classes from 57 kg to 125 kg
- Weightlifting: Classes from 55 kg to 109+ kg
- MMA: Featherweight (66 kg), Middleweight (84 kg), etc.
- Rowing: Lightweight (< 72.5 kg men, < 59 kg women)
- Judo: Multiple classes from 60 kg to 100+ kg
Equipment standards:
- Shot put: 7.26 kg (men), 4 kg (women)
- Discus: 2 kg (men), 1 kg (women)
- Javelin: 800 g (men), 600 g (women)
- Hammer throw: 7.26 kg (men), 4 kg (women)
Performance metrics:
- Clean and jerk records (kg lifted)
- Total weight lifted in competitions
- Body composition tracking
Manufacturing and Industry
Critical for quality control, material specifications, and product development. Enables consistent production and international standards.
Manufacturing uses:
- Raw materials: Ordered and inventoried in kg
- Product specifications: Component weights in kg or grams
- Quality control: Weight tolerance checking
- Batch production: Recipe scaling by kg
- Packaging: Box and pallet weights
- Shipping calculations: Product + packaging weight
- Waste management: Scrap material measured in kg
Industries:
- Automotive: Vehicle weight specifications
- Aerospace: Critical weight calculations
- Pharmaceuticals: Active ingredient quantities
- Chemicals: Formulation by weight
- Textiles: Fabric weight per square meter (GSM)
Agriculture and Farming
Standard for crop yields, animal weights, feed quantities, and agricultural commodities worldwide.
Agricultural uses:
- Crop yields: Tons per hectare (1,000 kg = 1 ton)
- Livestock weights: Animal growth tracking
- Feed calculations: Feed ratios per kg body weight
- Fertilizer application: kg per hectare
- Produce sales: Market prices per kg
- Seed quantities: Planting rates in kg/hectare
- Harvest records: Total yield in kg or tons
Example yields:
- Wheat: 3,000-8,000 kg/hectare
- Corn: 5,000-12,000 kg/hectare
- Rice: 4,000-10,000 kg/hectare
Everyday Life (Metric Countries)
Daily measurements for body weight, shopping, cooking, and general household use in 95% of the world's countries.
Personal use:
- Body weight tracking (bathroom scale)
- Grocery shopping (price per kg)
- Cooking and baking (recipe measurements)
- Luggage weight (travel)
- Baby weight monitoring (growth charts)
- Fitness tracking (weight loss/gain goals)
- Pet weight (veterinary care)
Use our kilogram converter for everyday conversions.
Additional Unit Information
About Milligram (mg)
How many milligrams are in a gram?
There are exactly 1,000 milligrams (mg) in one gram (g). This is a defined relationship in the metric system. The prefix "milli-" always means one-thousandth, so a milligram is one-thousandth of a gram.
To convert:
- Grams to milligrams: multiply by 1,000
- Milligrams to grams: divide by 1,000
Example: 3.5 g = 3,500 mg
How many milligrams are in a kilogram?
There are 1,000,000 (one million) milligrams in one kilogram. Since 1 kg = 1,000 g and 1 g = 1,000 mg, we multiply: 1,000 × 1,000 = 1,000,000 mg.
This large conversion factor is why kilograms are never used for medications—the numbers would be unwieldy. A 500 mg tablet would be "0.0005 kg," which is impractical and error-prone.
Convert milligrams to kilograms →
Is a milligram the same as a microgram?
No! A milligram (mg) is 1,000 times larger than a microgram (mcg or μg). This is one of the most dangerous medication errors in healthcare.
- 1 milligram (mg) = 1,000 micrograms (mcg)
- 1 microgram (mcg) = 0.001 milligrams (mg)
Some medications like levothyroxine, folic acid, and vitamin B12 are dosed in micrograms because the active doses are extremely small. Always verify which unit is intended, as confusing them can cause a 1,000-fold overdose or underdose.
Convert micrograms to milligrams →
What does "mg" stand for?
"mg" is the internationally recognized abbreviation for milligram. The "m" represents the metric prefix "milli-" (meaning 1/1,000), and "g" stands for gram. Together, "mg" means one-thousandth of a gram.
This abbreviation is standardized worldwide by the International System of Units (SI) and is understood across all languages and countries. Never use "mgs" with an "s"—the plural of "mg" is still "mg" (e.g., "500 mg," not "500 mgs").
How much does a milligram weigh in everyday terms?
A milligram is extremely light—almost imperceptible to human senses:
- 1 mg ≈ weight of a very small grain of sand
- 10 mg ≈ weight of a small feather fiber
- 100 mg ≈ weight of a single drop of water
- 1,000 mg = 1 gram = weight of a small paperclip
For comparison, a U.S. dollar bill weighs about 1 gram (1,000 mg), so 1 mg is 1/1,000th the weight of a dollar bill. Most household scales cannot accurately measure milligrams—you need a laboratory analytical balance.
Are milligrams used for measuring liquids?
Milligrams measure mass (weight), not volume. However, liquid medications are often prescribed in milligrams of the active ingredient, then measured in milliliters (mL) based on the concentration.
Example: A prescription might call for "500 mg of amoxicillin." If the bottle says "250 mg/5 mL," you'd measure 10 mL of the liquid to get 500 mg of the drug.
The key is understanding concentration: mg/mL tells you how many milligrams of active ingredient are in each milliliter of liquid.
Learn about medication concentrations →
How do I convert milligrams to ounces or pounds?
For converting between metric (mg) and imperial (oz, lb) units:
Milligrams to ounces:
- 1 ounce = 28,349.5 mg
- To convert mg to oz: divide mg by 28,349.5
Example: 50,000 mg ÷ 28,349.5 = 1.76 oz
Milligrams to pounds:
- 1 pound = 453,592 mg
- To convert mg to lb: divide mg by 453,592
Example: 100,000 mg ÷ 453,592 = 0.22 lb
These conversions are rarely used for medications (which stay in mg) but appear in industrial, commercial, or international shipping contexts.
Convert milligrams to ounces → Convert milligrams to pounds →
What is the difference between mass and weight when measuring milligrams?
Technically, mass is the amount of matter in an object (measured in mg, g, kg), while weight is the force of gravity on that mass. In everyday use and in medicine, these terms are used interchangeably, and we say "weight" when we mean "mass."
For practical purposes at Earth's surface, the distinction doesn't matter. A 500 mg tablet has 500 mg of mass and "weighs" 500 mg. The only time it matters is in scientific contexts involving gravity variations (like space) or high-precision physics experiments.
In medicine, pharmacy, and nutrition, "milligrams" always refers to mass, which is constant regardless of location or gravity.
Can I measure milligrams accurately at home?
Measuring true milligrams at home is challenging because most household scales lack sufficient precision:
Typical household scales:
- Kitchen scales: accurate to ±1-5 grams (not useful for mg)
- Food scales: accurate to ±0.1 grams = ±100 mg (limited use)
- Jewelry/pocket scales: accurate to ±0.01 g = ±10 mg (better, but still limited)
What you need for accurate mg measurements:
- Laboratory analytical balance: accurate to ±1 mg or ±0.1 mg
- Cost: $200-$2,000+ depending on precision
- Environment: Requires stable surface, no air currents, calibrated regularly
For medications: Never attempt to divide, measure, or adjust milligram doses at home without consulting a healthcare provider. Use pre-measured doses from pharmacies, and use provided measuring devices (syringes, droppers, cups) that are calibrated for the specific medication.
Learn about weight measurement tools →
Why are medications measured in milligrams instead of grams?
Milligrams are the standard for medications because most therapeutic doses fall conveniently between 1 mg and 1,000 mg, making the numbers practical to read and write without decimals:
- Easier to read: "500 mg" is clearer than "0.5 g"
- Reduces decimal errors: Writing "250 mg" prevents mistakes from misplaced decimal points in "0.250 g"
- International standard: The entire global pharmaceutical industry uses mg, ensuring consistency
- Appropriate scale: Most drug doses require precision at the milligram level
For very potent drugs requiring smaller amounts, micrograms (mcg) are used instead. For substances requiring larger amounts (like some electrolyte solutions), grams are used.
Convert between medication units →
How do milligrams relate to "mg/kg" dosing in medicine?
Many medications are dosed based on body weight using mg/kg (milligrams per kilogram). This adjusts the dose proportionally to patient size, which is especially important for children, neonates, and certain drugs with narrow therapeutic windows.
How it works:
- Patient weight is measured in kilograms
- Prescribed dose is given as mg/kg (e.g., "5 mg/kg")
- Total dose = weight (kg) × dose (mg/kg)
Example:
- Patient weighs 60 kg
- Drug dose: 10 mg/kg
- Total dose: 60 kg × 10 mg/kg = 600 mg
This ensures safe, effective dosing regardless of whether the patient is a 3 kg newborn or a 100 kg adult.
About Kilogram (kg)
How much is 1 kilogram visually?
One kilogram is about the weight of a liter bottle of water or a small laptop.
Visual comparisons:
- 1 liter of water: Exactly 1 kg (at 4°C)
- Bag of sugar: Typically 1 kg or 2 kg
- Small laptop: 1-1.5 kg
- Two pineapples: About 1 kg total
- Medium-sized book: Approximately 1 kg
- Loaf of bread: About 0.5-0.8 kg (1 kg for larger loaves)
Body reference:
- For most people, 1 kg is slightly heavier than can be easily held in one hand for extended periods
- About 2-3% of average adult body weight
To remember: Picture a standard milk or water bottle (1 liter) - that's 1 kilogram.
How many pounds are in a kilogram?
One kilogram equals approximately 2.20462 pounds, commonly rounded to 2.2 pounds.
Exact conversion: 1 kilogram = 2.204622622 pounds
Practical conversions:
- 1 kg ≈ 2.2 lb
- 5 kg ≈ 11 lb
- 10 kg ≈ 22 lb
- 50 kg ≈ 110 lb
- 70 kg ≈ 154 lb
- 100 kg ≈ 220 lb
Reverse conversion (pounds to kilograms):
- 1 pound = 0.453592 kg (about 0.45 kg)
- 10 pounds ≈ 4.5 kg
- 100 pounds ≈ 45.4 kg
- 150 pounds ≈ 68 kg
- 200 pounds ≈ 90.7 kg
Quick mental math:
- Multiply kg by 2 and add 10% for rough estimate
- Example: 50 kg × 2 = 100, + 10% = 110 lb
Use our kg to pounds converter for accurate conversions.
What is the difference between kilogram and gram?
Kilogram (kg) is 1,000 times larger than gram (g).
The relationship:
- 1 kilogram = 1,000 grams
- 1 gram = 0.001 kilograms (or 1/1,000 kg)
Conversion:
- To convert kg to g: multiply by 1,000
- To convert g to kg: divide by 1,000
When to use which:
Use grams (g) for:
- Small quantities (< 1 kg)
- Food ingredients (200g flour, 500g meat)
- Precious metals (gold, silver by the gram)
- Medications (pills in mg or g)
- Postal items under 1 kg
Use kilograms (kg) for:
- Body weight
- Larger food packages
- Most everyday objects
- Shipping packages
- Sports equipment
Examples:
- Smartphone: 200 grams = 0.2 kg
- Laptop: 1,500 grams = 1.5 kg
- Bag of rice: 5,000 grams = 5 kg
- Person: 70,000 grams = 70 kg
Convert: kg to grams | grams to kg
Is the kilogram used in the United States?
Yes and no - it depends on the context.
Where kilograms ARE used in the US:
- Science and research: All scientific work
- Medicine: Drug dosing, patient weights in hospitals
- Manufacturing: Especially export products
- Athletics: Olympic sports, international competition
- Import/export: International trade
- Automotive: Vehicle specifications (increasingly)
- Pharmaceuticals: All measurements
- Military: NATO standardization
Where kilograms are NOT commonly used:
- Grocery stores (pounds, not kg)
- Body weight (people say pounds)
- Cooking (recipes use cups, ounces)
- Bathroom scales (typically show pounds)
- Everyday conversation
- Food packaging (labeled in oz, lb)
The dual system:
- US products often show both: "1 lb (454g)" or "Net Wt 16 oz (1 lb) 453g"
- Scientific calculators and medical equipment use kg
- US is officially metric but hasn't converted fully
Fun fact: US currency is metric (100 cents = 1 dollar), but few Americans realize this!
How many grams are in a kilogram?
There are exactly 1,000 grams (g) in one kilogram.
Why 1,000?: The prefix "kilo-" means 1,000.
Conversion:
- 1 kilogram (kg) = 1,000 grams (g)
- To convert kg to g: multiply by 1,000
- To convert g to kg: divide by 1,000
Examples:
- 0.5 kg = 500 grams
- 1.5 kg = 1,500 grams
- 2.75 kg = 2,750 grams
- 5 kg = 5,000 grams
- 10 kg = 10,000 grams
Remember: Move the decimal point three places:
- Kg → g: Move right (1.5 kg = 1,500 g)
- G → kg: Move left (1,500 g = 1.5 kg)
Common weights:
- Smartphone: 150-250 g = 0.15-0.25 kg
- Bag of sugar: 1,000 g = 1 kg
- Newborn baby: 3,000-4,000 g = 3-4 kg
Use our kg to grams converter for instant conversions.
How is the kilogram defined today?
Current Definition (since May 20, 2019): The kilogram is defined by fixing the numerical value of the Planck constant at exactly 6.62607015×10⁻³⁴ joule-seconds (J⋅s).
What this means:
- No longer based on a physical object (the old platinum-iridium cylinder)
- Based on a fundamental constant of quantum mechanics
- Can be reproduced in any properly equipped laboratory worldwide
- Uses a device called a "Kibble balance" (formerly watt balance)
- Incredibly stable and will never change
Why this definition?:
- Universal: The Planck constant is the same everywhere in the universe
- Reproducible: Any lab with the right equipment can measure it
- Permanent: Physical objects degrade; constants don't
- Precise: More accurate than artifact-based definition
How it works: A Kibble balance measures mass by balancing it against electromagnetic force. By fixing the Planck constant, the electromagnetic force precisely defines mass.
Historical evolution:
- 1795: Mass of 1 liter of water
- 1889: Physical prototype (Le Grand K)
- 2019: Planck constant (current definition)
Why it matters: This was the last SI base unit to be redefined based on fundamental constants, completing the modernization of the metric system.
What does "kg" stand for?
"kg" is the symbol for kilogram.
Breaking it down:
- kilo-: Greek prefix meaning 1,000
- gram: Base unit of mass in the metric system
- kilogram: Literally "1,000 grams"
Symbol rules:
- Always lowercase "k" (not "Kg" or "KG")
- Lowercase "g"
- No period after "kg"
- Space between number and symbol: "5 kg" (not "5kg")
Other kilo- units:
- kilometer (km) = 1,000 meters
- kilowatt (kW) = 1,000 watts
- kilojoule (kJ) = 1,000 joules
- kilobyte (kB or KB) = 1,000 bytes
Interesting fact: The kilogram is unique among SI base units because it already contains a prefix ("kilo-"). The base unit is actually the gram, but kilogram is the official SI base unit for mass.
How do you convert kilograms to ounces?
To convert kilograms to ounces, multiply by approximately 35.274.
Conversion formula: ounces = kilograms × 35.274
Examples:
- 1 kg = 35.3 ounces
- 0.5 kg = 17.6 ounces
- 2 kg = 70.5 ounces
- 5 kg = 176.4 ounces
- 10 kg = 352.7 ounces
Reverse conversion (ounces to kilograms):
- 1 ounce = 0.0283495 kg (about 28.35 grams)
- 16 ounces (1 pound) = 0.4536 kg
- 32 ounces = 0.907 kg
- 100 ounces = 2.835 kg
Why 35.274?
- 1 kg = 2.20462 pounds
- 1 pound = 16 ounces
- 2.20462 × 16 = 35.274 ounces per kilogram
Quick mental math:
- 1 kg ≈ 35 oz (close enough for estimates)
- 0.5 kg ≈ 18 oz (just over 1 pound)
Use our kg to ounces converter for precise conversions.
What is 70 kg in pounds?
70 kilograms = 154.32 pounds (commonly rounded to 154 pounds).
Calculation: 70 kg × 2.20462 lb/kg = 154.32 lb
Context:
- Average adult: 70 kg is a typical weight for an average-height adult
- Healthy weight: For a 5'10" (178 cm) person, 70 kg is within healthy range
- Athletes: Many athletes in various sports weigh around 70 kg
Nearby conversions:
- 65 kg = 143 lb
- 70 kg = 154 lb
- 75 kg = 165 lb
- 80 kg = 176 lb
Body weight ranges (approximate):
- 50 kg = 110 lb (petite adult)
- 60 kg = 132 lb (average woman)
- 70 kg = 154 lb (average man)
- 80 kg = 176 lb (athletic/large build)
- 90 kg = 198 lb (large adult)
- 100 kg = 220 lb (very large adult)
Convert any weight: kg to pounds converter
How much does a kilogram weigh on Earth?
On Earth, 1 kilogram has a weight of approximately 9.8 newtons (N) at sea level.
Important distinction:
- Mass: 1 kilogram (constant everywhere)
- Weight: Force due to gravity = mass × gravitational acceleration
- On Earth: Weight (N) = 1 kg × 9.8 m/s² = 9.8 N
What this means:
- Your mass stays 1 kg everywhere
- Your weight changes based on gravitational strength
- On Earth, we feel this as "weight"
Weight on other celestial bodies (for 1 kg mass):
- Moon: 1.6 N (about 1/6 of Earth)
- Mars: 3.7 N (about 3/8 of Earth)
- Jupiter: 24.8 N (about 2.5× Earth)
- Sun: 274 N (about 28× Earth)
- International Space Station: ~8.7 N (microgravity, but not zero)
Why we say "weight in kilograms": In everyday language, "weight" means mass. Technically incorrect, but universally understood. Scientists use "mass in kilograms" and "weight in newtons" for precision.
Remember: Your bathroom scale measures mass (kg), not weight (newtons), but we casually call it "weight."
What is a metric ton vs kilogram?
Metric ton (also called tonne) = 1,000 kilograms.
The relationship:
- 1 metric ton = 1,000 kg
- 1 kilogram = 0.001 metric tons
Symbols:
- Metric ton: t or MT or tonne
- Kilogram: kg
When to use which:
Use kilograms (kg) for:
- Individual weights (< 1,000 kg)
- Body weight, packages, products
- Most everyday measurements
Use metric tons (tonnes) for:
- Heavy vehicles (cars, trucks)
- Industrial materials
- Bulk commodities
- Cargo shipping
- Agricultural yields
Examples:
- Small car: 1,000-1,500 kg = 1-1.5 metric tons
- Elephant: 5,000 kg = 5 metric tons
- Shipping container: 20,000-30,000 kg = 20-30 metric tons
- Wheat harvest: 100,000 kg = 100 metric tons
Confusion alert:
- Metric ton (1,000 kg) ≠ US ton (2,000 lb = 907 kg)
- Metric ton (1,000 kg) ≠ UK ton (2,240 lb = 1,016 kg)
- Always specify which ton!
Convert: kg to metric tons | metric tons to kg
Conversion Table: Milligram to Kilogram
| Milligram (mg) | Kilogram (kg) |
|---|---|
| 0.5 | 0 |
| 1 | 0 |
| 1.5 | 0 |
| 2 | 0 |
| 5 | 0 |
| 10 | 0 |
| 25 | 0 |
| 50 | 0 |
| 100 | 0 |
| 250 | 0 |
| 500 | 0.001 |
| 1,000 | 0.001 |
People Also Ask
How do I convert Milligram to Kilogram?
To convert Milligram to Kilogram, enter the value in Milligram in the calculator above. The conversion will happen automatically. Use our free online converter for instant and accurate results. You can also visit our weight converter page to convert between other units in this category.
Learn more →What is the conversion factor from Milligram to Kilogram?
The conversion factor depends on the specific relationship between Milligram and Kilogram. 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 Kilogram back to Milligram?
Yes! You can easily convert Kilogram back to Milligram by using the swap button (⇌) in the calculator above, or by visiting our Kilogram to Milligram converter page. You can also explore other weight conversions on our category page.
Learn more →What are common uses for Milligram and Kilogram?
Milligram and Kilogram are both standard units used in weight measurements. They are commonly used in various applications including engineering, construction, cooking, and scientific research. Browse our weight converter for more conversion options.
For more weight conversion questions, visit our FAQ page or explore our conversion guides.
Helpful Conversion Guides
Learn more about unit conversion with our comprehensive guides:
📚 How to Convert Units
Step-by-step guide to unit conversion with practical examples.
🔢 Conversion Formulas
Essential formulas for weight and other conversions.
⚖️ Metric vs Imperial
Understand the differences between measurement systems.
⚠️ Common Mistakes
Learn about frequent errors and how to avoid them.
All Weight Conversions
Metric Prefix Guide
Understanding Metric Prefixes
The metric system uses standard prefixes to indicate multiples or fractions of base units. For example, converting from milligram to kilogram involves a multiplication factor of 1000000000000000000.
| Prefix | Symbol | Power | Multiplier | Example |
|---|---|---|---|---|
| tera | T | 10¹² | 1,000,000,000,000 | teragram (Tg) |
| giga | G | 10⁹ | 1,000,000,000 | gigagram (Gg) |
| mega | M | 10⁶ | 1,000,000 | megagram (Mg) |
| kilo | k | 10³ | 1,000 | kilogram (kg) |
| hecto | h | 10² | 100 | hectogram (hg) |
| deca | da | 10¹ | 10 | decagram (dag) |
| (base) | 10⁰ | 1 | gram (g) | |
| deci | d | 10⁻¹ | 0.1 | decigram (dg) |
| centi | c | 10⁻² | 0.01 | centigram (cg) |
| milli | m | 10⁻³ | 0.001 | milligram (mg) |
| micro | μ | 10⁻⁶ | 0.000001 | microgram (μg) |
| nano | n | 10⁻⁹ | 0.000000001 | nanogram (ng) |
| pico | p | 10⁻¹² | 0.000000000001 | picogram (pg) |
Note: To convert between prefixed units, multiply or divide by powers of 10. For conversions betweenmilligram and kilogram, divide by 1000000000000000000.
Other Weight Units and Conversions
Explore other weight units and their conversion options:
- Gram (g) • Milligram to Gram
- Pound (lb) • Milligram to Pound
- Ounce (oz) • Milligram to Ounce
- Stone (st) • Milligram to Stone
- Ton (metric) (t) • Milligram to Ton (metric)
- Ton (US) (ton) • Milligram to Ton (US)
- Ton (UK) (long ton) • Milligram to Ton (UK)
- Microgram (µg) • Milligram to Microgram
- Carat (ct) • Milligram to Carat
- Slug (sl) • Milligram to Slug
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 — US standards for weight and mass measurements
International Organization for Standardization — International standard for mechanics quantities
Last verified: December 3, 2025