The Stone: Britain's Unusual Weight Unit
A 14-Pound Tradition
Try Weight Converter"I weigh 11 stone." For Americans, this sentence is incomprehensible. For Brits and Irish, it's the most natural way to discuss body weight. The stone is a unit of mass equal to 14 pounds (6.35 kg) that has been used in Britain for over 600 years and stubbornly persists today—even as the UK has otherwise adopted metric measurements.
History of the Stone
The stone has ancient origins, likely named because actual stones were used as weights in early trading. However, "a stone" meant different weights for different goods:
- Stone of wool: 14 pounds
- Stone of beef: 8 pounds (some regions)
- Stone of glass: 5 pounds
- Stone of wax: 12 pounds
The 14-pound stone became dominant because it was the standard for wool—medieval England's most important export. When Parliament standardized weights in 1824, the 14-pound stone became the only legal stone.
Conversion Table
| Stone | Pounds | Kilograms |
|---|---|---|
| 7 st | 98 lb | 44.5 kg |
| 8 st | 112 lb | 50.8 kg |
| 9 st | 126 lb | 57.2 kg |
| 10 st | 140 lb | 63.5 kg |
| 11 st | 154 lb | 69.9 kg |
| 12 st | 168 lb | 76.2 kg |
| 13 st | 182 lb | 82.6 kg |
| 14 st | 196 lb | 88.9 kg |
| 15 st | 210 lb | 95.3 kg |
| 16 st | 224 lb | 101.6 kg |
How to Express Stone Weight
In the UK and Ireland, body weight is expressed in stone and pounds:
- "10 stone" = 140 lb = 63.5 kg
- "10 stone 7" = 10 st 7 lb = 147 lb = 66.7 kg
- "10 and a half stone" = 10 st 7 lb
You never say "10.5 stone" with a decimal. Instead, the extra pounds are stated separately. Half a stone is 7 pounds.
Converting Your Weight
Pounds to stone:
- Divide by 14 to get stone
- The remainder is the extra pounds
Example: 165 lb ÷ 14 = 11 with remainder 11
Result: 11 stone 11 pounds
Where Stone Is Still Used
United Kingdom
Body weight is almost universally discussed in stone. Scales sold in the UK typically show stone/pounds as well as kilograms. Medical records may use kilograms, but people think in stone.
Ireland
Like the UK, Irish people use stone for personal weight despite the country being otherwise metric.
Australia (Historically)
Older Australians may remember their weight in stone from before metrication in the 1970s.
Not Used
The United States never adopted the stone. Americans use pounds exclusively (or kilograms in medical settings).
Why 14 Pounds?
The 14-pound stone relates to the old British weight system:
- 14 pounds = 1 stone
- 2 stone (28 lb) = 1 quarter
- 4 quarters (112 lb) = 1 hundredweight (cwt)
- 20 hundredweight (2,240 lb) = 1 long ton
This system made sense for the wool trade, where wool was sold in standard sacks and bales based on these units. The math worked out evenly in the days before calculators.
Common Body Weights
| Description | Stone | Pounds | Kilograms |
|---|---|---|---|
| Small woman | 7-8 st | 98-112 lb | 44-51 kg |
| Average woman | 9-11 st | 126-154 lb | 57-70 kg |
| Average man | 11-13 st | 154-182 lb | 70-83 kg |
| Large man | 14-16 st | 196-224 lb | 89-102 kg |
The Stone's Future
Despite UK metrication efforts since the 1970s, the stone refuses to disappear. Unlike most imperial units that have faded from everyday use, the stone remains deeply embedded in British culture for discussing body weight.
Interestingly, EU regulations that prohibited displaying imperial units on scales (requiring metric-only) were relaxed in 2007 to allow supplementary imperial displays—a small victory for the stone.
Conclusion
The stone is a quirky survivor of Britain's imperial past—a 14-pound unit that persists in the 21st century purely through cultural inertia. For travelers to the UK or Ireland, or anyone communicating with Brits about weight, understanding the stone is essential.
Just remember: 1 stone = 14 pounds = 6.35 kg. And unlike most weights, you express remainders in pounds, not decimals: "10 stone 7," not "10.5 stone."