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Weight and mass are two of the most commonly measured quantities in daily life — from checking your body weight at the gym to weighing ingredients while cooking, from shipping packages to measuring gold at a jewellery store. The challenge is that different countries use different systems: most of the world uses kilograms and grams (metric), while the United States uses pounds and ounces (imperial). Converting between these systems accurately is essential in cooking, fitness, trade, logistics, and science.
Though used interchangeably in everyday language, mass and weight are physically different:
For most practical conversions — cooking, fitness, shipping — mass is what we measure, and the terms are used interchangeably.
Quick reference for the most commonly used weight and mass conversions:
| From | To | Multiply By |
|---|---|---|
| Kilograms (kg) | Pounds (lb) | 2.20462 |
| Pounds (lb) | Kilograms (kg) | 0.453592 |
| Kilograms (kg) | Grams (g) | 1,000 |
| Grams (g) | Ounces (oz) | 0.035274 |
| Ounces (oz) | Grams (g) | 28.3495 |
| Pounds (lb) | Grams (g) | 453.592 |
| Stone (st) | Kilograms (kg) | 6.35029 |
| Metric Ton (t) | Kilograms (kg) | 1,000 |
| Carat (ct) | Grams (g) | 0.2 |
| System | Unit | Symbol | Common Use |
|---|---|---|---|
| Metric | Milligram | mg | Medicine, chemistry |
| Metric | Gram | g | Cooking, food labels |
| Metric | Kilogram | kg | Body weight, trade |
| Metric | Metric Ton | t | Industry, shipping |
| Imperial | Ounce | oz | Food, US recipes |
| Imperial | Pound | lb | Body weight (US), trade |
| Imperial | Stone | st | Body weight (UK) |
| Imperial | Short Ton | tn | US industry |
| Other | Carat | ct | Gemstones, gold |
1 kilogram = 1,000 grams. The prefix "kilo" means one thousand in the metric system.
1 kilogram = 2.20462 pounds. Conversely, 1 pound = 0.453592 kg. This is the most commonly needed conversion for body weight between metric and imperial countries.
1 pound = 16 ounces. This is the standard imperial relationship — used in US cooking recipes and food packaging.
1 stone = 6.35029 kilograms = 14 pounds. Stone is primarily used in the UK and Ireland for expressing body weight.
A metric ton (tonne) = 1,000 kg = 2,204.62 lb. A short ton (US ton) = 907.185 kg = 2,000 lb. The metric ton is used worldwide; the short ton is used mainly in the United States.
1 gram = 1,000 milligrams. Milligrams are commonly used in medicine for drug dosages and in nutrition labels for vitamins and minerals.
1 carat = 0.2 grams = 200 milligrams. The carat is the standard unit for measuring the weight of gemstones and diamonds internationally.