Pounds and stone
The avoirdupois pound is exactly 0.45359237 kilograms (1959 agreement) and contains 16 ounces. Body weight, food and product weights in the US, and body weight alongside stone in the UK, use pounds.
The stone is exactly 14 pounds, or 6.35029318 kilograms. People in the UK and Ireland often state body weight in stone and pounds, for example 11 st 4 lb.
Worked example
Convert 168 lb: 168 × 0.07142857143 = 12, so 168 pounds is 12 stone. Likewise 100 lb = 7.142857143 st.
Estimating in your head
Divide by 14 for a quick figure; it is off by about 0%. For 168 lb that gives 12 st, against 12 exactly.
Going the other way
To convert stone to pounds, divide by 0.07142857143 (or multiply by 14). The swap button between the boxes opens that page.
How this works
st = lb × 0.07142857143
1 lb = 0.45359237 kg and 1 st = 6.35029318 kg, both by definition, so the factor is their ratio: 0.07142857143 (rounded here; the page uses the full value). Results drop binary floating-point noise beyond 15 significant digits and display at the precision you choose (6 significant figures by default). Copy result copies the full value.
Frequently asked
How many stone are in a pound?
1 pound = 0.07142857143 stone. The factor is exact by definition but has endless decimals, so it is shown rounded; the page uses the full value.
How do I convert pounds to stone?
Multiply by 0.07142857143. For example, 100 lb × 0.07142857143 = 7.142857143 st.
What is 1,000 lb in stone?
1,000 lb = 71.42857143 st. The table next to the converter lists more common values.
Is the result rounded?
Only on screen. The page computes with the exact definitions and removes floating-point noise past 15 significant digits; pick 3 to 12 significant figures, or use Copy result for the full value.
Sources
- NIST SP 811 Appendix B.8 — Factors for units listed alphabetically
- Federal Register 59-5442 (1959) — Refinement of values for the yard and the pound
- Wikipedia — Avoirdupois system
Reviewed Oct 17, 2026 · test vectors fixtures/units/mass/lbs-to-stone/