Convert between kilograms, grams, pounds, ounces, stones, tonnes and troy ounces.
Enter the values to see the result here.
Formula
All weights are expressed in kilograms, then converted:
xto=xfrom×ftoffrom
with f in kilograms: gram 0.001, pound 0.45359237, ounce 0.028349523125, stone 6.35029318, troy ounce 0.0311034768, tonne 1000. One pound is 16 ounces and one stone is 14 pounds.
Worked example
Convert 150 lb to kilograms.
150×0.45359237=68.0389 kg.
In stone: 68.0389/6.35029=10.71 stone, or 10 stone 10 lb.
Check with the common shortcut of halving and subtracting 10%: 150/2.2=68.18 kg, which is 0.2% off.
Common mistakes
Using the troy ounce for kitchen items or the ordinary ounce for gold.
Confusing the US ton (2000 lb), long ton (2240 lb) and metric tonne (1000 kg). This tool uses the metric tonne.
Writing 10 st 10 lb as 10.10 stone. It is 10 + 10/14 = 10.71 stone.
Rounding the pound factor to 0.45 for anything beyond a rough guess.
Frequently asked questions
Is a pound exactly 0.45 kg?
No. The international avoirdupois pound is defined as exactly 0.45359237 kg. Using 0.45 understates weight by about 0.8%, which is 0.6 kg on a 75 kg person.
What is a troy ounce?
A troy ounce (31.1035 g) is used for gold, silver and platinum. It is about 10% heavier than the ordinary ounce (28.3495 g), so gold prices quoted per ounce are per troy ounce.
Do mass and weight mean the same here?
In everyday use yes. Strictly, kilograms and pounds measure mass; weight is the force from gravity. For shopping, cooking and health the distinction does not matter.
How many stone is 70 kg?
70 kg ÷ 6.35029 = 11.02 stone, which is 11 stone and 0.3 lb, or about 154.3 lb.