Inch Converter — Inches to cm, mm, feet, metres
Type any number of inches and instantly see the equivalent in millimetres, centimetres, metres, kilometres, feet, yards and miles — all using the exact SI definition of 1 inch = 25.4 mm.
in
1 inch = 2.54 cm (exact SI definition)
- 1
Conversion factor
2.541 inch = 2.54 cm exactly — the 1959 International Yard and Pound Agreement definition. - 2
厘米
12 × 2.54 = 30.4800
这个计算器是如何工作的？
One inch is exactly 25.4 mm or 2.54 cm. Multiply inches by 2.54 for centimetres, by 0.0254 for metres, divide by 12 for feet, divide by 36 for yards. All conversions are exact — 1 inch = 25.4 mm is a definition, not a rounded figure.
公式
How this is calculated
The inch has been defined as exactly 25.4 millimetres since the 1959 International Yard and Pound Agreement between the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa. This is an exact definition — there is no rounding — so all metric conversions in this calculator are mathematically exact. Multiply by 2.54 for centimetres, 0.0254 for metres, 0.0000254 for kilometres.
Within the imperial/US customary system, 12 inches make 1 foot, 36 inches make 1 yard, and 63 360 inches make 1 mile. Dividing by these integers gives the respective conversions, which are also exact by definition.
Common reference points: a standard A4 sheet of paper is 11.69 inches tall; a US letter sheet is 11 inches; a typical smartphone screen is 5–7 inches diagonally; a foot is 12 inches; a metre is approximately 39.37 inches.
常见问题
1 inch is exactly 2.54 centimetres. This has been the international definition since 1959 and is exact — not an approximation.
Divide the total inches by 12. The whole number part is feet; the remainder (modulo 12) is inches. For example, 65 inches = 5 feet 5 inches (65 ÷ 12 = 5 remainder 5).
Yes. Both the US customary inch and the UK imperial inch were redefined as exactly 25.4 mm in 1959, so they are identical.
也称为
TG we-Calculate Editorial Team. (2026). Inch Converter — Inches to cm, mm, feet, metres [Online calculator]. TG we-Calculate. https://we-calculate.com/zh/calculator/inch-converter
TG we-Calculate Editorial Team. "Inch Converter — Inches to cm, mm, feet, metres." TG we-Calculate. 2026. https://we-calculate.com/zh/calculator/inch-converter.
TG we-Calculate Editorial Team, "Inch Converter — Inches to cm, mm, feet, metres," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/zh/calculator/inch-converter
@misc{wecalculate_inch_converter, title = {Inch Converter — Inches to cm, mm, feet, metres}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/zh/calculator/inch-converter}}, year = {2026}, note = {TG we-Calculate} }
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