Mass Converter
Kilograms, pounds, ounces, stone and tonnes for cooking, luggage and body weight
Kilograms, pounds, ounces, stone and tonnes for cooking, luggage and body weight. No data leaves your browser – every conversion happens locally.
Kilograms, pounds and the less common units
The kilogram is the base unit. A pound is defined as exactly 0.45359237 kg, an ounce is a sixteenth of that (28.349523125 g) and a stone is 14 pounds. That's why kg to lb conversions match to every decimal place across properly built converters.
The slug is in the list for engineering work. It's the mass that accelerates at 1 ft/s² under a force of one pound-force, about 14.59 kg, and it turns up in US physics textbooks more than in real life.
Watch out for gold and silver. Bullion prices use the troy ounce (31.1035 g), which isn't included here. The ounce in this tool is the everyday avoirdupois ounce, about 10% lighter.
Common weight conversions
| 1 kg | 2.205 lbs |
| 1 lb | 453.6 g |
| 1 stone | 6.35 kg |
| 1 oz | 28.35 g |
| 100 lbs | 45.36 kg |
| 70 kg | 154.3 lbs |
Good to know
Stone is a UK thing
Stone (14 lbs) is used for body weight in the UK and Ireland but almost nowhere else. 11 stone = 154 lbs = 69.85 kg.
Metric tons vs short tons
A metric ton (tonne) is 1,000 kg = 2,205 lbs. A US short ton is 2,000 lbs = 907 kg. They're not the same, so context matters.
Worked examples
Checked bag allowance
Many airlines cap economy bags at 23 kg. That's 50.71 lb, which is why US carriers write the same limit as 50 lb.
Newborn weight
A 3.4 kg baby is 7.5 lb. Split the decimal into ounces (0.5 × 16) and you get the 7 lb 8 oz that relatives in the US or UK will ask about.
Baking from a UK recipe
250 g of butter is 8.82 oz, a little over two US sticks (each stick is 4 oz).
Body weight in kilograms, pounds and stone
Bathroom scales in India and Europe read kilograms, US scales read pounds, and UK doctors and gyms still talk in stone. The stone column splits pounds into whole stone (14 lb each) plus the pounds left over.
| Kilograms | Pounds | Stone and pounds |
|---|---|---|
| 50 kg | 110.2 lb | 7 st 12.2 lb |
| 55 kg | 121.3 lb | 8 st 9.3 lb |
| 60 kg | 132.3 lb | 9 st 6.3 lb |
| 65 kg | 143.3 lb | 10 st 3.3 lb |
| 70 kg | 154.3 lb | 11 st 0.3 lb |
| 75 kg | 165.3 lb | 11 st 11.3 lb |
| 80 kg | 176.4 lb | 12 st 8.4 lb |
| 90 kg | 198.4 lb | 14 st 2.4 lb |
| 100 kg | 220.5 lb | 15 st 10.5 lb |
Decimal pounds and other weight slip-ups
The converter gives decimal pounds, and decimals aren't ounces. 7.5 lb is 7 lb 8 oz, because 0.5 × 16 = 8, not 7 lb 5 oz. The same goes for stone: 11.5 st is 11 st 7 lb (0.5 × 14), which is 73.03 kg.
Kitchen scales cause the other common error. A recipe that lists "8 oz" of flour means weight, but a recipe that lists "8 fl oz" of milk means volume. They only line up for water and similar liquids. For dry ingredients, weigh rather than convert a cup measure.