| Inches (in) | Centimetres (cm) |
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To convert inches to centimetres, multiply by 2.54. One inch is defined as exactly 2.54 centimetres — this is a fixed international definition since 1959:
This is an exact conversion with no rounding in the definition. 12 inches = 1 foot = 30.48 cm exactly.
Useful reference points for inches to cm:
To convert inches to centimetres, multiply by 2.54. One inch is defined as exactly 2.54 cm — this exact definition has been internationally agreed since 1959. For example, 6 inches = 6 × 2.54 = 15.24 cm. A 12-inch ruler = 30.48 cm. A height of 72 inches (6 feet) = 182.88 cm.
To go the other way (cm to inches), multiply by 0.393701 or divide by 2.54. For instance, 100 cm = 100 × 0.393701 = 39.37 inches ≈ 3 feet 3.37 inches. This is also the basis for our cm to inches converter.
Inches are widely used in the United States and, for some measurements (screen sizes, tyre widths, pipe diameters), also in the UK. Centimetres are the metric standard used in Europe, Australia, and most of the world for body measurements, product dimensions, and engineering. You'll need this conversion when buying TVs or monitors (screen sizes are in inches globally), ordering clothing from metric-sized countries, reading furniture dimensions, or converting US body measurements to metric for medical or fitness records.
One inch equals exactly 2.54 centimetres. This is the international definition since 1959. To convert inches to cm, multiply by 2.54. To convert cm to inches, multiply by 0.393701.
5 inches = 5 × 2.54 = 12.7 cm. A standard US letter sheet of paper is 8.5 × 11 inches = 21.59 × 27.94 cm (similar to A4 at 21 × 29.7 cm).
30 cm = 30 × 0.393701 = 11.811 inches ≈ 11 13/16 inches. This is close to 1 foot (12 inches = 30.48 cm). A 30 cm ruler is sometimes called a '12-inch ruler'.
Multiply the feet by 30.48 and the inches by 2.54, then add. For example, 5 ft 8 in = (5 × 30.48) + (8 × 2.54) = 152.4 + 20.32 = 172.72 cm.
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