Why Americans Don't Use Stone
The US and UK share a language but not a bathroom scale. Here is the colonial history behind the split.
The Short Answer: America Left Before the Stone Was Standardised
The United States inherited English weights in the 1600s and 1700s, when the stone was still an informal trade unit with regional variations. American independence came in 1776, nearly 60 years before Britain's 1835 Weights and Measures Act fixed the stone at exactly 14 pounds for all trade.
By the time the stone became official in Britain, America had already built its own system around the pound as the standard unit for body weight. There was no reason to adopt a "new" British unit, and every reason to keep the pound everyone already used.
How the Split Happened
1600s-1700s
Colonial America uses English units. The pound is the everyday weight unit; the stone appears occasionally for goods like wool but never standardises for body weight.
1776
American independence. The new nation keeps English units out of practicality but begins diverging from British standards.
1835
Britain's Weights and Measures Act fixes the stone at 14 pounds. America, now independent, is unaffected and continues with pounds.
1866
The US legalises the metric system but never mandates it. The pound remains the customary unit; the stone is never adopted.
Today
Americans weigh in pounds, Britons in stone and pounds. The two systems are mutually unintelligible without conversion.
Pounds vs Stone-and-Pounds: The Practical Difference
An American says "I weigh 165 pounds". A Briton of identical weight says "11 stone 11". Same person, same mass, completely different numbers. This causes genuine confusion: a Briton telling an American friend they "lost half a stone" gets a blank stare, and an American saying "I'm 200 pounds" sounds alarming to British ears until you convert it (14 stone 4, perfectly ordinary).
| US (pounds) | UK (stone) | KG |
|---|---|---|
| 140 lb | 10 st 0 lb | 63.5 kg |
| 160 lb | 11 st 6 lb | 72.6 kg |
| 180 lb | 12 st 12 lb | 81.6 kg |
| 200 lb | 14 st 4 lb | 90.7 kg |
Travelling between the two countries? Our pounds to stone converter translates instantly, and the conversion chart covers every value.
Frequently Asked Questions
Why don't Americans use stone for weight?
The US developed its customary system from English units before the stone was standardised for trade in 1835. The pound became the default body-weight unit, and there was never a reason to adopt stone later. By then, pounds were doing the job perfectly well.
Do Americans know what a stone is?
Most do not. The stone is essentially unknown in the US outside of people with British connections. An American hearing '10 stone' would have no intuitive sense of the weight.
What do Americans use instead of stone?
Pounds. An American says 'I weigh 160 pounds' where a Briton says '11 stone 6'. US medical records, scales, and media all use pounds.
Did America ever use the stone?
Colonial America used English units, including occasional stone references for goods like wool. But it never became the standard for body weight, and metrication debates in the US focused on pounds vs kilograms, never involving stone.
Is the stone used in any other country besides the UK?
Ireland uses it much like the UK does. Beyond those two, no other country uses stone for body weight in everyday life.