Weight Converter — Fast, Exact Mass & Unit Calculations
Weight & Mass Converter
Universal Weight Conversion: Standards, Formulas & Practical Applications
Welcome to Weight Converter Hub — the precision metrology platform for instant weight and mass conversions across metric, imperial, and British customary units. Whether you are calculating personal body weight on UK bathroom scales (stones and pounds), measuring culinary baking ingredients (grams and ounces), sizing athletic gym barbell plates (kilograms and pounds), or calculating commercial logistics shipping cargo (metric tonnes and US short tons), verified mathematical factors are essential.
Under the landmark 1959 International Yard and Pound Agreement, standard measurement systems are internationally harmonized. Specifically, 1 avoirdupois pound (lb) is defined as exactly 0.45359237 kilograms, 1 British stone is defined as exactly 14 pounds (6.35029318 kg), and 1 avoirdupois ounce is defined as exactly 28.349523125 grams. In the International System of Units (SI), mass is fundamentally linked to the Planck constant (h = 6.62607015 × 10⁻³⁴ J·s), standardizing the kilogram as the global benchmark.
Different regions follow distinct everyday measurement conventions. In the United Kingdom and Ireland, personal health and fitness weights are traditionally tracked in stones and pounds (e.g., 14.5 stone = 14 st 7 lb = 92.08 kg or 140 lbs = 10 stone), while medical dosages strictly utilize kilograms. In India and across Asia, the decimal metric system is universal, with high-frequency everyday lookups between grams (gm), kilograms (kg), and metric tonnes for culinary recipes and agricultural trade. In the United States, customary pounds and short tons (2,000 lbs = 907.185 kg) remain commercial shipping standards. Our live engine performs 64-bit IEEE 754 floating-point math across all units simultaneously, eliminating rounding errors and ensuring laboratory accuracy.
How to Use This Weight Converter
To convert any weight or mass, enter your numerical quantity into the input field, choose your origin unit from the dropdown or quick-switch chips, and select your preferred decimal places. All eight units update simultaneously with live mathematical precision.
Enter Quantity
Type your number in the main field. You can enter whole numbers, decimals, or scientific notation like 2.5e3.
Choose Origin Unit
Select kilograms, pounds, grams, ounces, stones, milligrams, metric tons, or US short tons using the dropdown or quick chips.
Set Decimal Places
Adjust the precision selector between 2, 4, 6, or 8 decimal places depending on whether you need kitchen estimates or laboratory accuracy.
Read or Copy Values
Read instant results across all eight units in the synchronized grid, or click Copy to copy any converted value to your clipboard.
Weight Conversion Chart
A weight conversion chart provides an instant printable reference for everyday masses without requiring manual calculations. Below are four essential lookup tables generated directly from our verified dataset, covering metric kilograms, imperial pounds, kitchen grams, and British stones.
Kilograms to Pounds (kg to lb)
View full chart →| Kilograms (kg) | Pounds (lb) |
|---|---|
| 1 kg | 2.20 lb |
| 2 kg | 4.41 lb |
| 3 kg | 6.61 lb |
| 4 kg | 8.82 lb |
| 5 kg | 11.02 lb |
| 6 kg | 13.23 lb |
| 7 kg | 15.43 lb |
| 8 kg | 17.64 lb |
| 9 kg | 19.84 lb |
| 10 kg | 22.05 lb |
| 20 kg | 44.09 lb |
| 30 kg | 66.14 lb |
| 40 kg | 88.18 lb |
| 50 kg | 110.23 lb |
| 55 kg | 121.25 lb |
| 60 kg | 132.28 lb |
| 65 kg | 143.30 lb |
| 70 kg | 154.32 lb |
| 75 kg | 165.35 lb |
| 80 kg | 176.37 lb |
| 85 kg | 187.39 lb |
| 90 kg | 198.42 lb |
| 95 kg | 209.44 lb |
| 100 kg | 220.46 lb |
Pounds to Kilograms (lb to kg)
View full chart →| Pounds (lb) | Kilograms (kg) |
|---|---|
| 1 lb | 0.45 kg |
| 2 lb | 0.91 kg |
| 3 lb | 1.36 kg |
| 4 lb | 1.81 kg |
| 5 lb | 2.27 kg |
| 6 lb | 2.72 kg |
| 7 lb | 3.18 kg |
| 8 lb | 3.63 kg |
| 9 lb | 4.08 kg |
| 10 lb | 4.54 kg |
| 20 lb | 9.07 kg |
| 30 lb | 13.61 kg |
| 40 lb | 18.14 kg |
| 50 lb | 22.68 kg |
| 100 lb | 45.36 kg |
| 150 lb | 68.04 kg |
| 200 lb | 90.72 kg |
| 250 lb | 113.40 kg |
| 300 lb | 136.08 kg |
Grams to Ounces (g to oz Kitchen Values)
View full chart →| Grams (g) | Ounces (oz) |
|---|---|
| 1 g | 0.035 oz |
| 5 g | 0.176 oz |
| 10 g | 0.353 oz |
| 25 g | 0.882 oz |
| 50 g | 1.764 oz |
| 100 g | 3.527 oz |
| 250 g | 8.818 oz |
| 500 g | 17.637 oz |
| 1000 g | 35.274 oz |
Kilograms to Stone & Pounds (Body Weight)
View full chart →| Kilograms (kg) | Stone & Pounds |
|---|---|
| 50 kg | 7 st 12.2 lb |
| 55 kg | 8 st 9.3 lb |
| 60 kg | 9 st 6.3 lb |
| 65 kg | 10 st 3.3 lb |
| 70 kg | 11 st 0.3 lb |
| 75 kg | 11 st 11.3 lb |
| 80 kg | 12 st 8.4 lb |
| 85 kg | 13 st 5.4 lb |
| 90 kg | 14 st 2.4 lb |
| 95 kg | 14 st 13.4 lb |
| 100 kg | 15 st 10.5 lb |
Formulas and Exact Conversion Factors
Every weight conversion factor on this website is legally defined by an exact mathematical ratio to the kilogram. Converting mass requires either multiplying by the unit\'s factor in kilograms or dividing by the reciprocal factor, guaranteeing zero rounding drift.
| Unit Name | Symbol | Exact Value in Kilograms | Conversion Rule |
|---|---|---|---|
| Kilogram | kg | 1.0 kg (SI Base Unit) | Base reference unit |
| Pound (avoirdupois) | lb | 0.45359237 kg exactly | Multiply kg by 2.20462262 or lb by 0.45359237 |
| Gram | g | 0.001 kg exactly | Divide grams by 1,000 to get kg |
| Ounce (avoirdupois) | oz | 0.028349523125 kg exactly | Multiply oz by 28.349523125 to get grams |
| Stone | st | 6.35029318 kg exactly (14 lb) | Multiply stones by 14 for lbs, or 6.35029 for kg |
| Milligram | mg | 0.000001 kg exactly | Divide milligrams by 1,000,000 to get kg |
| Metric Ton (Tonne) | t | 1,000 kg exactly | Multiply tonnes by 1,000 to get kg |
| US Short Ton | ton | 907.18474 kg exactly (2,000 lb) | Multiply short tons by 2,000 to get pounds |
Three Step-by-Step Worked Conversion Examples
Example 1: Kilograms to Pounds (kg to lb)
Convert an adult body weight of 75 kg into imperial pounds.
75 kg × 2.20462262 = 165.3467 lbResult: 75 kg is about 165.35 pounds rounded to two decimal places.
Example 2: Ounces to Grams (oz to g)
Convert an 8 oz baking portion of flour into metric grams.
8 oz × 28.349523125 g = 226.7962 gResult: 8 ounces is about 226.80 grams for culinary recipes.
Example 3: Stone to Kilograms (st to kg)
Convert a British body weight of 12 stone into kilograms.
12 st × 6.35029318 kg = 76.2035 kgResult: 12 stone equals about 76.20 kg.
Weight vs Mass: The Fundamental Difference
In physics, mass is the intrinsic quantity of matter inside an object measured in kilograms, which never changes regardless of location. Weight is the downward gravitational force acting upon that mass, measured in newtons. A 70 kg person has 70 kg of mass on Earth, on the Moon, or in deep space.
The confusion between weight and mass arises because everyday scales operate on the Earth\'s surface under standard gravity (approximately 9.80665 m/s²). Because local gravity remains nearly constant anywhere on Earth, spring and strain-gauge scales can measure downward force and instantly divide by 9.80665 to display your mass in kilograms or pounds.
However, if you stepped onto a digital bathroom scale on the Moon, it would read only about 16.5% of your Earth weight because lunar gravity is much weaker. Yet your physical body mass—the actual matter comprising your cells and bones—would remain identical. In science and commerce, kilograms and avoirdupois pounds measure mass directly.
Metric vs Imperial vs US Customary Systems
The metric system is the decimal standard used by international science and most countries worldwide, built on base units like the kilogram. The British imperial system and US customary system share historical avoirdupois roots but differ significantly in ton capacities and stone usage.
| Measurement System | Primary Mass Units | Where Used Globally | Defining Characteristic |
|---|---|---|---|
| International Metric (SI) | Kilograms (kg), Grams (g), Tonnes (t) | Global standard; all countries except US, Myanmar, Liberia | Decimal multipliers based on powers of 10 |
| US Customary System | Pounds (lb), Ounces (oz), Short Tons (2,000 lb) | United States commercial retail & daily life | Based on the 1959 international avoirdupois pound |
| British Imperial System | Stone (st = 14 lb), Pounds (lb), Long Tons (2,240 lb) | United Kingdom, Ireland (body weight and informal trade) | Retains stone for personal weight and long tons for freight |
The Metric System (SI)
Governed by the BIPM, the metric system simplifies mass calculations because units scale by exact decimal factors of 10. One kilogram equals 1,000 grams, one gram equals 1,000 milligrams, and one metric tonne equals 1,000 kilograms. This eliminates complex fractional math in laboratory research, medicine, and international trade.
US Customary System
In the United States, grocery products, personal body scales, and shipping couriers rely on avoirdupois pounds and ounces. Sixteen ounces make up one pound, and 2,000 pounds constitute one US short ton (907.185 kg). The US system does not traditionally use the stone unit for human weight.
British Imperial System
While the United Kingdom officially adopted the metric system for commercial trade, the imperial stone (14 pounds) remains widely used across the UK and Ireland for describing adult body weight. Additionally, the historic British long ton equals 2,240 pounds (1,016.05 kg), exactly 160 stone.
Popular Weight Conversions
Explore our twenty specialized supporting conversion pages and printable reference charts below. Each tool provides dedicated formulas, worked examples, pair-specific lookup tables, and metrological validation for culinary, fitness, travel, and freight calculations.
Kilograms & Pounds (kg & lb)
- KG to LBS = 1 kg is 2.20462 lbs (Kilograms to Pounds)1 kilogram (kg) equals 2.20462262 pounds (lbs).
- LBS to KG = 1 lb is 0.45359 kg (Pounds to Kilograms)1 pound (lb) equals 0.45359237 kilograms (kg) exactly.
- kg to lbs ChartPrintable kg to lbs conversion chart: 1 kg = 2.2046 lbs, 50 kg = 110.23 lbs, 100 kg = 220.46 lbs, covering 1 to 500 kg.
- kg to Pounds and Ounces Converter (kg to lb oz)3.5 kg equals 7 pounds and 11.5 ounces (7 lb 11.5 oz), and 1 kg equals 2 pounds and 3.27 ounces.
- Pounds and Ounces to kg Converter (lb oz to kg)7 pounds 8 ounces (7 lb 8 oz) equals 3.4019 kilograms (3.40 kg), and 8 lbs equals 3.63 kg.
Grams, Ounces & Pounds (g, oz & lb)
- Grams to Ounces = 28.35 g per oz (Exact g to oz Tool)1 gram (g) equals 0.03527396 ounces (oz), and 1 ounce equals exactly 28.349523125 grams.
- Ounces to Grams Converter: 1 oz = 28.3495 g (oz to g)1 ounce (oz) equals 28.349523125 grams (g) exactly.
- LBS to OZ = 1 lb is 16 oz (Exact Pounds to Ounces)1 pound (lb) equals 16 ounces (oz) exactly.
- OZ to LBS = 16 oz in 1 lb (Exact Ounces to Pounds)1 ounce (oz) equals 0.0625 pounds (lb) exactly, and 16 ounces equals 1 pound.
- Grams to LBS = 453.59 g in 1 lb (Exact g to lbs Tool)1 gram (g) equals 0.00220462262 pounds (lb), and 1,000 grams equals 2.20462 lbs.
- Kilograms to Ounces Converter: 1 kg = 35.274 oz (kg to oz)1 kilogram (kg) equals 35.27396195 ounces (oz).
Stone & Body Weight (st & lb)
- Stones to KG = 1 st is 6.3503 kg (Stone to Kilograms)1 stone (st) equals 6.35029318 kilograms (kg), and 14 pounds equals 1 stone.
- KG to Stones = 1 kg is 0.1575 st (Kilograms to Stone)1 kilogram (kg) equals 0.15747304 stones (st), or 0.1575 stone.
- Stones to LBS = 1 st is 14 lbs (Stone to Pounds Math)1 stone (st) equals 14 pounds (lb) exactly.
- Stone and Pounds to kg Calculator (st + lb)12 stone 5 pounds equals 78.47 kilograms (78.4715 kg). Total pounds multiplied by 0.45359237 yields kilograms.
- kg to Stone and Pounds Calculator (kg to st lb)70 kilograms (kg) equals 11 stone 0.3 pounds (11 st 0.32 lb), or 154.32 pounds total.
- Stones to KG Chart: Printable Stone to kg Table GridPrintable stone to kg chart: 1 st = 6.35 kg, 10 st = 63.50 kg, 11 st = 69.85 kg, 12 st = 76.20 kg, covering 1 to 30 stone with half stones.
Industrial Tons & Freight (t & ton)
Scientific Guidance & Reference
Trending Calculators & High-Demand Benchmarks
- Weight Difference CalculatorCalculate exact variance, weight loss/gain gaps, and percentage changes between two measurements
- Kilograms to Grams Converter1 kilogram (kg) equals exactly 1,000 grams (g) with culinary conversion table
- Grams to Kilograms Converter1,000 grams (g) equals exactly 1.0 kilogram (kg) with metric shift rule
- Ounces to Kilograms Converter16 ounces equals 0.453592 kg (1 oz = 0.02835 kg) postal weight conversion
- Stones to Kilograms Chart (1 to 30 st)Printable British body weight lookup table covering all whole and half-stone values
- 13.5 Stone in KG (13 st 7 lbs)13.5 stone equals exactly 85.73 kg (189 lbs) instant conversion benchmark
- 10.5 Stone in KG (10 st 7 lbs)10.5 stone equals exactly 66.68 kg (147 lbs) instant UK body weight answer
- 9.5 Stone in KG (9 st 7 lbs)9.5 stone equals exactly 60.33 kg (133 lbs) instant calculation with formula
- 15.5 Stone in KG (15 st 7 lbs)15.5 stone equals exactly 98.43 kg (217 lbs) instant personal weight answer
Where Weight Conversion Is Used
Accurate weight conversion is essential across international travel, food preparation, athletic training, logistics, and commerce. Whenever equipment, recipes, or billing rates originate from a different country, converting units ensures safety, compliance, and consistent outcomes.
Culinary Arts & Baking
Baking relies on exact baker\'s percentages. Converting European recipes measured in grams to American ounces prevents dry cakes and dense bread loaves.
Fitness & Barbell Plates
Olympic weightlifting uses 20 kg barbells and metric plates, while commercial gyms often stock 45 lb discs. Converting weights ensures accurate training logs.
Airline Luggage Limits
International airlines strictly enforce checked baggage allowances of 23 kg or 32 kg (about 50.7 lb and 70.5 lb), where a slight conversion mistake incurs overweight baggage fees.
Parcel Shipping & Logistics
Freight carriers compute billable charges based on weight thresholds in kilograms or pounds. Accurate mass calculations avoid unexpected courier surcharges.
Jewellery & Precious Metals
Precious gold and silver are weighed in grams or specialized troy ounces, where tiny decimal differences carry significant monetary value.
Frequently Asked Questions
Find concise answers to the most frequent mass and weight conversion questions below, including exact conversion factors, imperial stone definitions, and the scientific distinction between mass and weight.
How do I convert kg to pounds?
To convert kilograms to pounds, multiply your value in kilograms by 2.20462262 (or divide by 0.45359237). For example, 70 kg multiplied by 2.20462 equals about 154.32 pounds. You can also use our free conversion tool above for instant calculations.
How many pounds are in a kilogram?
There are approximately 2.20462262 pounds in one kilogram. To explore the exact mathematical factor and worked examples, visit our dedicated how many pounds in a kg guide.
How many ounces are in a pound?
There are exactly 16 avoirdupois ounces in one pound (1 lb = 16 oz). You can verify this standard ratio and kitchen examples on our how many ounces in a pound reference page.
How many grams are in an ounce?
There are exactly 28.349523125 grams in one avoirdupois ounce under the 1959 International Yard and Pound Agreement. For common baking and culinary conversions, review our how many grams in an ounce guide.
What is a stone in weight and how many pounds is it?
A stone is a traditional British imperial unit of mass equal to exactly 14 pounds (about 6.35029 kg). Learn how stones and pounds are used for human body weight on our how many kg in a stone page.
Is a ton the same as a tonne?
No, a US short ton equals 2,000 pounds (907.185 kg), whereas a metric tonne (spelled with an 'ne') equals exactly 1,000 kilograms (2,204.62 pounds). The imperial long ton equals 2,240 pounds (1,016.05 kg).
What is the difference between a short ton and a long ton?
A short ton is standard in the United States and equals 2,000 pounds (907.185 kg). A long ton was traditionally used in the United Kingdom and equals 2,240 pounds (160 stones or 1,016.05 kg).
What is the difference between weight and mass?
Mass represents the invariant quantity of matter in an object and is measured in kilograms. Weight is the downward gravitational force exerted on that mass and is measured in newtons. Everyday scales are calibrated to read mass directly.
How accurate is this weight converter?
Our converter calculates all units through kilograms using exact constants from the 1959 Agreement and IEEE 754 64-bit floating-point math. Displayed numbers are rounded to your chosen decimal precision without intermediate truncation.
About Our Conversion Data
All conversion factors on Weight Converter Hub are strictly grounded in the historic 1959 International Yard and Pound Agreement, which legally established that one avoirdupois pound equals exactly 0.45359237 kilograms.
Our calculation algorithms follow NIST Special Publication 811 guidelines and SI standards maintained by the International Bureau of Weights and Measures (BIPM). We do not use third-party estimation APIs or rounded conversion shortcuts.
Read our full Conversion Methodology and Rounding Policy →