Kg to Stone Converter

A stone is a British unit of weight equal to 14 pounds, which is exactly 6.35029318 kg. Smart scales, fitness apps, clinics and doctors abroad often give weight in kilograms. Friends, family and slimming groups in the UK and Ireland still tend to talk in stone and pounds, so this tool turns a kg reading into the form they use.

What Kg to Stone Conversion Measures

It changes the unit, not the weight. 70 kg and 11 st 0.3 lb are the same weight written two ways. It does not judge your weight.

The Formula

UK law defines the stone as 14 pounds and the pound as 0.45359237 kg¹. NIST lists the same stone and states that the pound is exactly 453.59237 grams².

Pounds = kilograms / 0.45359237

Stone = whole number of (pounds / 14)

Pounds left over = pounds - 14 x stone

Decimal stone = kilograms / 6.35029318

How This Calculator Computes Your Result

Type your weight in kilograms (decimals are fine). Choose how to show the pounds: to 0.1 lb (the default), to the nearest half pound, or to whole pounds.

The tool rounds your total pounds first, and only then splits them into stone and pounds. 63.5 kg is 139.99 lb. Split first, and you get 9 st 13.99 lb, which rounds to the impossible "9 st 14 lb". Round first, and you get 140.0 lb, which is 10 st 0 lb. Decimal stone shows 2 decimals and comes straight from your kilograms.

What Your Result Means

The pounds part of your answer always runs from 0 to just under 14. This table covers 40 to 160 kg in 5 kg steps.

A quick sanity check: every 6.35 kg adds one stone, and every kilogram adds about 2.2 lb. So 70 kg is just over 11 stone, and 100 kg is 15.75 stone (15 st 10.5 lb).

Why Your Reading Is in Kilograms

Clinics often weigh in kilograms because many medicines are dosed by body weight. A US national council on medication errors recommends that hospitals record weight in metric units only and lock scales out of pounds³. It warns that a weight in pounds recorded as kilograms can more than double a dose³. Home scales are different. An NHS leaflet notes that they can show kilograms, pounds or stone, and digital ones usually have a button to change the unit⁴.

Tracking Weight Loss in Stone

UK health news often gives weight change in stone, even when it was measured in kilograms. For example, NHS England reported that people on its soups and shakes diet lost an average of 7.2 kg ("over one stone") after one month and 13.4 kg ("over two stone") in three months⁵. The math backs this up: 7.2 kg is 1 st 1.9 lb, and 13.4 kg is 2 st 1.5 lb.

You can enter a weight change as well as a weight. A full stone is 6.35 kg, and half a stone is 3.18 kg.

For fair comparisons, the NHS suggests weighing on the same scales, at the same time of day, in similar clothing⁴. To see your loss as a share of your starting weight, use the Weight Loss Percentage Calculator.

Common Kg to Stone Mistakes

• Reading the decimal as pounds. 80 kg is 12.60 st, and .60 of a stone is 0.60 x 14 = 8.4 lb. So 80 kg is 12 st 8.4 lb, not 12 st 6 lb.

• Using 2.2 lb per kilogram. It reads about 0.46 lb low per 100 kg, which can tip a result near a whole stone: 63.5 kg x 2.2 gives 9 st 13.7 lb, but the exact answer rounds to 10 st 0 lb.

• Splitting before rounding, which gives a "14 lb" leftover.