Formulas & exact factors
- 1 stone =
14 lb(exact) - 1 lb =
0.45359237 kg(exact) - 1 stone =
6.35029318 kg(exact)
From pounds to stones: stones = pounds ÷ 14.
Split as stones + lb: st = ⌊pounds ÷ 14⌋, lb_rem = pounds − 14×st.
From stones + lb to pounds: pounds = 14×st + lb_rem.
To kilograms: kg = pounds × 0.45359237.
Examples
154 lb → 154 ÷ 14 = 11 st (exact), kg = 154×0.45359237 = 69.85322498 kg.
12 st 5 lb → pounds = 12×14 + 5 = 173 lb → kg ≈ 78.472 kg.
FAQ
Where is “stone” used?
Primarily in the UK and Ireland for body weight. It’s not an SI unit but is widely recognized in those contexts.
Why do you show both decimal stones and stones+lb?
Decimal stones are useful for quick math (e.g., 11.5 st), while stones+lb (e.g., 11 st 7 lb) match how people report weight informally.
Formula (LaTeX) + variables + units
This section shows the formulas used by the calculator engine, plus variable definitions and units.
Formula (extracted LaTeX)
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Formula (extracted text)
1 stone = 14 lb (exact) 1 lb = 0.45359237 kg (exact) 1 stone = 6.35029318 kg (exact) From pounds to stones: stones = pounds ÷ 14. Split as stones + lb: st = ⌊pounds ÷ 14⌋, lb_rem = pounds − 14×st. From stones + lb to pounds: pounds = 14×st + lb_rem. To kilograms: kg = pounds × 0.45359237.
Variables and units
- No variables provided in audit spec.
Sources (authoritative):
- NIST — Weights and measures — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/weights-and-measures - NIST — SI units — nist.gov · Accessed 2026-01-19
https://www.nist.gov/pml/owm/metric-si/si-units
Changelog
Version: 0.1.0-draft
Last code update: 2026-01-19
Last code update: 2026-01-19
0.1.0-draft · 2026-01-19
- Initial audit spec draft generated from HTML extraction (review required).
- Verify formulas match the calculator engine and convert any text-only formulas to LaTeX.
- Confirm sources are authoritative and relevant to the calculator methodology.