Stone and 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.
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.
Worked example
Convert 11 st: 11 × 14 = 154, so 11 stone is 154 pounds. Likewise 20 st = 280 lb.
Estimating in your head
The factor is a short exact number, so mental math needs no rounding: multiply by 14.
Going the other way
To convert pounds to stone, divide by 14 (or multiply by 0.0714285714286). The swap button between the boxes opens that page.
How this works
lb = st × 14
1 st = 6.35029318 kg and 1 lb = 0.45359237 kg, both by definition, so the factor is their ratio: 14 exactly. 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 pounds are in a stone?
1 stone = 14 pounds, exactly. The value follows from the unit definitions, so it never changes.
How do I convert stone to pounds?
Multiply by 14. For example, 20 st × 14 = 280 lb.
What is 100 st in pounds?
100 st = 1,400 lb. 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/stone-to-lbs/