Stones to Kilograms

How Many Kilograms in a Stone?

1 stone equals 6.35029 kilograms (or exactly 14 pounds). The stone is primarily used in the United Kingdom and Ireland for measuring body weight. If someone in the UK says they weigh '12 stone', that's 76.2 kg or 168 lbs. To convert stones to kilograms, multiply by 6.35029.

How to Convert Stone to Kilogram

1. Start with the weight in stones (st). If given as stones and pounds (e.g., 11 st 4 lbs), first convert the pounds to a decimal: 4 lbs ÷ 14 = 0.286 stone, so 11 st 4 lbs = 11.286 st.
2. Multiply by 6.35029 to get kilograms.
3. For a quick estimate, multiply stones by 6.35 or use: stones × 6 + stones × 0.35.
4. Alternatively, convert to pounds first (stones × 14) then to kg (pounds × 0.4536).
5. Example: 13 stone × 6.35029 = 82.55 kg.

Real-World Examples

History of Stone and Kilogram

The stone as a unit of weight dates back to at least the 14th century, when it was used across Northern Europe for trade — particularly for weighing wool, which was England's most important export commodity. The problem was that the stone varied wildly by region and commodity: a stone of wool was 14 pounds, a stone of beef was 8 pounds, and a stone of glass was 5 pounds. In 1389, a royal statute fixed the stone at 14 pounds for wool, and this became the general standard. The stone was officially included in the British Weights and Measures Act until 1985, when the UK legally adopted the metric system. Despite this, British and Irish people still overwhelmingly describe their body weight in stones and pounds rather than kilograms.

Common Mistakes to Avoid

• Forgetting that 1 stone = 14 lbs, not 10. Because stone sounds like a round-number unit, people sometimes assume decimal divisions. But stones divide into 14 pounds, so 10 st 10 lbs is not 10.10 stone — it's 10 + (10/14) = 10.714 stone.
• Assuming stones are used globally. Outside the UK and Ireland, virtually no one uses stones. If you're communicating weight internationally, convert to kg (most of the world) or lbs (US). Using stones with non-British audiences will cause confusion.
• Confusing stones with metric tons or other units. A stone (6.35 kg) is a measure of personal body weight in British culture. It has no relationship to geological stones or construction materials.

Frequently Asked Questions