Weight Converter: kg, lb, oz, g, Stone and Tons

How to use the weight converter

Type the weight you have, pick the unit it is in, then pick the unit you want. The main result shows the converted figure, and underneath you always see the same weight in kilograms, pounds, grams, ounces and stone-and-pounds, so you can read off several units at once.

Results are calculated to 10 significant figures and shown rounded, which is far more precise than any kitchen or bathroom scale.

The formula

Every unit is defined exactly in grams, so the converter changes your weight into grams and then into the target unit: result = value × (grams per from-unit) ÷ (grams per to-unit).

The exact definitions used are: 1 pound = 453.59237 g, 1 ounce = 28.349523125 g (1/16 lb), 1 stone = 14 lb = 6,350.29318 g, 1 US short ton = 2,000 lb = 907,184.74 g, 1 UK long ton = 2,240 lb = 1,016,046.9088 g, and 1 metric tonne = 1,000 kg. These are international legal definitions, so the conversions are exact, not estimates.

For stone and pounds, the total pounds are divided by 14: the whole number is the stone, and the remainder (rounded to 0.1 lb) is the pounds.

Worked example

Convert 70 kg to pounds. 70 kg is 70,000 g. Dividing by 453.59237 g per pound gives 154.3235835 lb, shown as 154.3236.

For stone: 154.3236 ÷ 14 = 11 whole stone, which accounts for 154 lb. The remaining 0.3236 lb rounds to 0.3, so 70 kg reads as 11 st 0.3 lb.

Practical tips

A quick mental check: 1 kg is about 2.2 lb, and 1 lb is about 0.45 kg. If your answer is wildly different, check the unit selections.

Be careful with "ton". In the US a ton is 2,000 lb, in the UK an older ton is 2,240 lb, and a metric tonne is 1,000 kg (about 2,204.6 lb). Shipping and freight documents usually mean the metric tonne.

Fluid ounces measure volume, not weight. This tool uses avoirdupois ounces, the ones used for food and body weight. For cups and millilitres, use a cooking measurement converter instead.

Frequently asked questions