Weight Converter
Convert between metric and imperial weight units instantly.
Last updated: August 2026 · Written and verified by Akash Pandey
Convert weight
kilograms
This runs the same calculation engine as the main scientific calculator, entirely in your browser. Nothing you type is sent anywhere.
Mass vs weight - and why this converter ignores gravity
Mass (kg, lb) is the amount of matter in an object; weight is the force gravity exerts on that mass, measured in newtons. This distinction rarely matters day to day, because everyone weighs objects on Earth, where the ratio between the two is constant. It becomes real the moment gravity changes: an object with 70 kg of mass weighs about 686 N on Earth but only about 113 N on the Moon - the mass has not changed, but the weight has. Every conversion on this page is a mass conversion; "weight" in the everyday sense (what a scale shows) is what is being converted.
Common weight conversions
| From | To | Multiply by |
|---|---|---|
| Kilograms | Pounds | 2.20462 |
| Pounds | Kilograms | 0.453592 |
| Ounces | Grams | 28.3495 |
| Grams | Ounces | 0.035274 |
| Stones | Kilograms | 6.35029 |
Not all ounces are the same
The ounce on a kitchen scale (avoirdupois, 28.3495 g) is not the ounce used to price gold, silver, or platinum. Precious metals are weighed in troy ounces, at 31.1035 g - about 10% heavier. A "1 oz gold coin" contains 31.1 g of gold, not 28.3 g. Using the wrong ounce when pricing metal is a genuine and common mistake, since both units share the same name and abbreviation in casual use.
Real-world uses
- Airline baggage allowances - many international economy limits are 23 kg (50.7 lb); US domestic carriers often quote 50 lb (22.7 kg) instead, so the same suitcase can be compliant on one route and over on another.
- Baking by weight - professional and European recipes give ingredients in grams rather than cups, because weight is precise and volume (a "cup" of flour) compresses unpredictably.
- Shipping and freight - courier pricing tables are usually in kg, while US retail packaging lists ounces and pounds.
- Precious metals - gold and silver spot prices are quoted per troy ounce worldwide, regardless of the local everyday weight unit.
| Unit | Equivalent | Used in |
|---|---|---|
| 1 kilogram | 2.20462 pounds | Worldwide (science, trade) |
| 1 pound | 16 ounces | US, UK everyday |
| 1 stone | 14 pounds | UK body weight |
| 1 troy ounce | 31.1035 g | Gold, silver, precious metals |
| 1 metric tonne | 1,000 kg | Industrial, shipping |
| 1 US ton | 2,000 lb (907 kg) | US industrial |
Worked examples
Will a 32 kg suitcase clear a 50 lb airline limit?
32 × 2.20462
- Given: bag mass 32 kg, limit 50 lb. Different units, so compare after converting.
- Method: convert kilograms to pounds using the kg-to-lb factor.
- Calculation:
32 × 2.20462 = 70.55. - Interpretation: 70.55 lb is well over the 50 lb limit - the bag needs to lose about 20 lb (roughly 9 kg) to comply.
= 70.55 lb - over the limit
A recipe wants 4 oz of butter; your scale reads grams
4 × 28.3495
- Given: 4 oz, kitchen (avoirdupois) ounces - not troy.
- Method: multiply by the oz-to-g factor for everyday weight.
- Calculation:
4 × 28.3495 = 113.398. - Interpretation: measure out approximately 113 g on the scale.
= ≈113 g
- The same unity-fraction logic used here
- Use a converted weight to calculate BMI
- Work out how far over a baggage limit you are, in percent
Frequently Asked Questions
What is a troy ounce, and why is it heavier than a normal ounce?
A troy ounce (31.1035 g) is the historical unit for weighing precious metals and gemstones, distinct from the everyday avoirdupois ounce (28.3495 g) used for food and general goods. Gold and silver prices worldwide are quoted per troy ounce - using the everyday ounce to price metal understates the true weight by about 10%.
What is a stone, and why does the UK still use it?
A stone is 14 pounds (about 6.35 kg), historically one of a set of standardised trade weights. It survives specifically for reporting UK/Ireland adult body weight ("11 stone 4"), while nearly everything else in Britain - groceries, parcels, medicine - has moved to metric.
Is mass the same thing as weight?
No. Mass is how much matter an object contains; weight is the gravitational force on that mass. On Earth the two track each other so closely that people use the words interchangeably, but a scale actually measures a gravitational force and reports it as if it were mass, which is only valid at Earth-surface gravity.
My airline says 23 kg but my scale is in pounds - how do I check?
Convert the limit, not your bag: 23 kg × 2.20462 ≈ 50.7 lb. If your bag reads under about 50.7 lb, it clears a 23 kg limit. Converting the limit once, rather than re-converting your bag's weight every time, avoids repeating the arithmetic.
Why do US and metric recipes give different-feeling ingredient amounts?
US recipes typically measure dry ingredients by volume (cups, tablespoons), which varies with how packed the ingredient is. Metric and professional recipes measure by weight (grams), which is unambiguous - a "cup of flour" can vary by 20% between two people, but 120 g of flour is always 120 g.
How do I convert pounds to kilograms quickly?
Divide by 2.2. For example, 150 lb ÷ 2.2 ≈ 68.2 kg. The exact factor is 2.20462, but 2.2 is close enough for most practical purposes.
What is the difference between mass and weight on a scale?
Scales measure the force of gravity on an object (weight) but display it as mass (kilograms or pounds). This is only accurate at Earth-surface gravity. On the Moon, a scale calibrated for Earth would read about one-sixth of the true mass.
Why are precious metals weighed in troy ounces instead of regular ounces?
Historical convention from the medieval French town of Troyes, where international trade used this unit. The troy system also divides differently (12 troy ounces per pound vs 16 avoirdupois), reflecting its origins in coinage and metal trading.