Convert height from cm to feet and inches and back, and weight from kg to pounds or stones and pounds, using the exact 2.54 cm inch.
180 cm is 5 ft 11 in (70.87 in), and 75 kg is 165.3 lb, or 11 st 11 lb.
1 in = 2.54 cm exactly (1959 international yard and pound agreement).
Rounded to the nearest inch, then 12 in = 1 ft.
1 lb = 0.45359237 kg exactly.
Rounded to the nearest pound, then 14 lb = 1 st.
A height in centimetres becomes feet and inches by dividing by 2.54 cm per inch, rounding to the nearest inch and splitting into feet of 12 inches. A body weight in kilograms becomes pounds by dividing by 0.45359237 kg per pound, and stones and pounds by rounding to the nearest pound and splitting into stones of 14 pounds.
The default, 180 cm and 75 kg, gives 5 ft 11 in (70.87 in) and 165.3 lb, or 11 st 11 lb. Typing 5 ft 11 in or 11 st 4 lb straight into the fields works the other way.
Both factors are exact by the 1959 international yard and pound agreement, so the only approximation is the rounding to whole inches and pounds, which carries upward: 71.85 in shows as 6 ft 0 in, not 5 ft 12 in.
Checked against: 180 / 2.54 = 70.866 in → 71 in = 5 ft 11 in; 75 / 0.45359237 = 165.347 lb = 11 st 11.35 lb (Python fractions)
Checked against: 71 × 2.54 = 180.34 cm; 158 lb × 0.45359237 = 71.66759446 kg (NIST HB 44)
Checked against: 182.5 / 2.54 = 71.85 in → 72 in = 6 ft 0 in; 13 st 13.6 lb = 195.6 lb → 196 lb = 14 st 0 lb
Checked against: 152.4 / 2.54 = 60 in exactly
5 ft 11 in. 180 cm ÷ 2.54 = 70.87 in, which rounds to 71 in, and 71 in is 5 × 12 + 11. Six feet (72 in) is exactly 182.88 cm; with rounding to the nearest inch, any height from 181.61 cm (71.5 in) upward shows as 6 ft 0 in.
Turn the height into inches, then multiply by 2.54. 5 ft 11 in is 5 × 12 + 11 = 71 in, and 71 × 2.54 = 180.34 cm. The factor is exact: the 1959 international yard and pound agreement fixed the inch at 2.54 cm, so any error comes only from how many decimals you keep.
14 pounds, so one stone is exactly 6.35029318 kg (14 × 0.45359237 kg). A weight of 11 st 4 lb is 158 lb, or 71.67 kg. The stone remains in customary use for body weight in the United Kingdom and Ireland, and for weigh-ins in boxing and horse racing there.
11 st 11 lb. 75 kg ÷ 0.45359237 kg/lb = 165.35 lb, which rounds to 165 lb; 165 = 11 × 14 + 11, so the weight is 11 stone 11 pounds. In pounds alone it is 165.3 lb, and 12 stone (168 lb) would be 76.2 kg.
Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 4 worked examples whose answers come from independent sources; for example, “180 cm and 75 kg” is checked against 180 / 2.54 = 70.866 in → 71 in = 5 ft 11 in; 75 / 0.45359237 = 165.347 lb = 11 st 11.35 lb (Python fractions).
NIST Handbook 44, Appendix C — inch, foot, pound and stone.
4 worked examples with independently sourced answers ship with this calculator. They run in the test suite; you can run them here too.
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