Stone to KG Converter

How the conversion works

A stone is defined as 14 pounds, and since 1959 the pound has been fixed at exactly 0.45359237 kilograms — so one stone is exactly 6.35029318 kg:

• stone → kg: multiply by 6.35029 — 11 st × 6.35029 = 69.85 kg
• kg → stone: divide by 6.35029 — 80 kg ÷ 6.35029 = 12.6 st

Because both factors are definitions, the conversion is exact; any rounding in results comes only from trimming decimals for readability.

Body weight in the UK and Ireland is usually spoken as stones and pounds — "11 stone 4" means 11 st 4 lb. To convert that form, divide the pounds by 14 and add: 11 + 4/14 = 11.29 st, then multiply by 6.35029 to get about 71.67 kg.

Quick reference table

How to use it

1. Type a value into either field — stone or kilograms.
2. The other side converts live; results are trimmed to two decimals.
3. Tap a common value chip (8–16 st) to start from a typical body weight.
4. Copy puts the full conversion (e.g. 11 st = 69.85 kg) on your clipboard.

For a weight like "12 st 6 lb", enter 12.43 stone (6 ÷ 14 = 0.43) and read off the kilograms.

When you need this

The stone lives almost entirely in body-weight territory: British and Irish bathroom scales, gym membership forms, weight-loss goals and everyday conversation all use stones, while medical records, fitness apps and the rest of the world use kilograms. Tracking weight loss across the two systems — or moving between a UK doctor and an app that only accepts kg — is the classic reason to convert.

For weight in pounds instead, the KG to LBS Converter works the same way, and the Ounces to Grams Converter covers small kitchen weights. Once you have your weight in kilograms, the BMI Calculator can put it in context against your height.

Private by design

The conversion runs in your browser — nothing is uploaded or tracked, and there's no sign-up. For other unit pairs, the general Unit Converter covers length, volume, temperature and more, or browse more free utilities on the all tools page.