⚖️ Weight Converter
By ToolNimba Editorial Team · Updated 2026-06-19
Type in any box and every other unit updates instantly.
Convert weight and mass between metric and imperial units in one place: kilograms, grams, tonnes, pounds, ounces and stone. Type a value into any field below and the rest update instantly, so you can go from kg to lbs, pounds to kg or grams to ounces without reaching for a separate chart. Every conversion uses the exact internationally defined factors, not the rounded 2.2 shortcut, so the numbers match official references.
What is the Weight Converter?
Most of the world measures mass with the metric system, where the base unit is the kilogram (kg). Smaller masses are given in grams (1 kg = 1000 g) and larger ones in tonnes (1 tonne = 1000 kg). The imperial and US customary systems use the pound (lb), which splits into 16 ounces (oz), and in the UK the stone (1 stone = 14 lb) is still common for body weight. These two families do not line up neatly, which is why a converter is handy.
The cleanest way to convert is to route everything through the kilogram, because the pound has an exact legal definition in terms of it: 1 lb = 0.45359237 kg exactly. From that single anchor, every other factor follows. To turn pounds into kilograms you multiply by 0.45359237, and to go the other way you divide (or multiply by its reciprocal, 2.2046226). Grams, tonnes, ounces and stone are then just fixed multiples of the kilogram or the pound, so the tool converts your input to kilograms first and then out to the unit you want.
A quick note on wording: in everyday use people say weight when they really mean mass. Mass is the amount of matter in an object and stays the same everywhere, while weight is the force gravity exerts on that mass and changes with location (you would weigh less on the Moon). The kilogram and pound used here are units of mass. Bathroom scales report mass even though we call the reading weight, so for day to day purposes the distinction rarely matters, but it is worth knowing when a question is really about force (measured in newtons).
When to use it
- Converting a recipe that lists ingredients in grams and ounces.
- Reading your body weight in kg when scales or forms expect pounds or stone.
- Checking baggage or parcel limits quoted in kg against a scale that reads in pounds.
- Logging gym or barbell loads where plates are marked in kg but a program is written in lb.
How to use the Weight Converter
- Type the amount you know into its matching field (for example kilograms).
- Read the converted value in the unit you need (pounds, ounces, stone, grams or tonnes).
- Switch the value in any field and every other unit recalculates at once.
Formula & method
Worked examples
Convert 70 kg to pounds.
- Multiply by the exact factor: 70 × 2.2046226
- = 154.32 lb
Result: 70 kg = 154.32 lb
Convert 150 lb to kilograms.
- Multiply by 0.45359237: 150 × 0.45359237
- = 68.04 kg
Result: 150 lb = 68.04 kg
Convert 10 stone to kilograms.
- 1 stone = 6.35029318 kg, so multiply: 10 × 6.35029318
- = 63.50 kg (equivalent to 140 lb)
Result: 10 stone = 63.50 kg
Exact mass conversion factors
| Unit | Equivalent |
|---|---|
| 1 kilogram (kg) | 2.2046226 lb, 35.273962 oz, 1000 g |
| 1 pound (lb) | 0.45359237 kg, 16 oz, 453.59237 g |
| 1 ounce (oz) | 28.349523 g, 0.0625 lb |
| 1 stone | 14 lb, 6.35029318 kg |
| 1 gram (g) | 0.001 kg, 0.03527396 oz |
| 1 tonne (t) | 1000 kg, 2204.6226 lb |
Common mistakes to avoid
- Confusing pounds and ounces. There are 16 ounces in a pound, not 100. A reading of 5 lb 8 oz is 5.5 lb, not 5.08 lb.
- Mixing mass and force. Pounds and kilograms here are units of mass. Force is measured in newtons (or pounds-force), so do not equate a kg reading with a newton value.
- Rounding kg to exactly 2.2 lb. The factor is 2.2046226, not 2.2. The shortcut adds roughly 0.2% of error, which grows noticeable on heavy loads.
Glossary
- Kilogram (kg)
- The base SI unit of mass, equal to 1000 grams.
- Pound (lb)
- An imperial and US customary unit of mass, defined as exactly 0.45359237 kg.
- Ounce (oz)
- A sixteenth of a pound, about 28.35 grams.
- Stone
- A UK unit of mass equal to 14 pounds (about 6.35 kg), used mainly for body weight.
- Tonne (t)
- A metric unit equal to 1000 kilograms, also called a metric ton.
Frequently asked questions
How many lbs in a kg?
One kilogram equals about 2.2046226 pounds. So to convert kilograms to pounds you multiply by roughly 2.2046, and to go back you divide by the same figure.
What is 70 kg in pounds?
70 kg is about 154.32 pounds. The calculation is 70 × 2.2046226 = 154.32 lb, which is also roughly 11 stone.
How do I convert pounds to kg?
Multiply the number of pounds by 0.45359237 to get kilograms. For example, 150 lb × 0.45359237 = 68.04 kg. A rough mental shortcut is to divide pounds by 2.2.
How many pounds in a stone?
There are 14 pounds in one stone. So 10 stone is 140 lb, and to turn stone into pounds you multiply by 14.
How many grams are in an ounce?
One ounce is about 28.35 grams (28.349523 g exactly). A pound, being 16 ounces, is therefore 453.59 grams.
Is weight the same as mass?
Not strictly. Mass is the amount of matter and does not change with location, while weight is the gravitational force on that mass. The kilogram and pound used here are mass units, though in everyday speech people use weight to mean the same thing.