Pounds to Stone Converter

The pounds-to-stone converter instantly translates any weight in pounds (lb) into stones and pounds — the format you will see on every UK bathroom scale, NHS letter, and GP chart. It also shows the equivalent in kilograms (kg) so you can move between British, American, and metric systems without reaching for pen and paper.

How it works

The calculation uses two exact, internationally agreed conversion factors:

• 1 stone = 14 lb (exact, by definition in the UK Weights and Measures Act and the international avoirdupois system)
• 1 lb = 0.45359237 kg (exact, by the 1959 international avoirdupois agreement between the USA, Canada, Australia, South Africa, New Zealand, and the UK)

To split decimal pounds into stones and pounds:

stones = floor(lb / 14) remaining lb = lb mod 14

For example, 160 lb: floor(160 / 14) = 11 stones, remainder = 160 - 154 = 6 lb, so the answer is 11 st 6 lb.

To obtain kilograms, multiply the total pound figure by 0.45359237. Because this factor is exact, the only rounding involved is the display precision you choose.

Worked example — a 154 lb adult

A person who weighs 154 pounds wants to know their weight in the British convention for a GP form:

1. Divide by 14: 154 / 14 = 11.0 exactly.
2. Whole number = 11 stones, remainder = 0 lb.
3. In kilograms: 154 × 0.45359237 = 69.85 kg (to 2 d.p.).

So 154 lb = 11 st 0 lb = 69.85 kg. Because 154 is a multiple of 14, there are zero remaining pounds — a neat example that also lets you verify the tool quickly.

A second example: 175 lb.

1. floor(175 / 14) = 12 stones (12 × 14 = 168)
2. Remainder: 175 - 168 = 7 lb
3. Result: 12 st 7 lb = 79.38 kg

Why does the UK still use stones?

The stone has been embedded in British culture since at least the 14th century and became standardised at 14 lb by the Weights and Measures Act 1835. Despite metrication in most trade contexts, body weight is the one area where public use of the stone persists — NHS patient records routinely display weight as “12 st 4 lb” alongside the metric equivalent. Bathroom scales sold in the UK nearly always include a st/lb mode. The USA, by contrast, never adopted the stone, which is why transatlantic confusion is common. This tool covers all three systems simultaneously so you never need to convert twice.

Formula summary

All arithmetic in this tool is performed at full JavaScript floating-point precision (64-bit IEEE 754 double), then rounded only for display. No data leaves your browser.