Inches to cm Converter

How to convert inches to cm

One inch is defined as exactly 2.54 centimeters, so the conversion is a single multiplication:

• cm = inches × 2.54
• To go the other way: inches = cm ÷ 2.54

For example, 12 inches × 2.54 = 30.48 cm (one foot), and a 32-inch TV is about 81 cm across. Type a value into either box above and the paired field, the 0–36 inch progress bar and the chart update instantly — clear a box and the other clears too.

Inches to cm conversion chart

These are the inch values people look up most, from a single inch up to a yard (36 inches). Useful for screen sizes, clothing and body measurements, paper and picture-frame sizes, and any US spec you need in metric:

Why 2.54 is the exact factor

The inch and the centimeter come from two different measurement systems — imperial and metric — that were only formally reconciled in 1959, when the inch was fixed at exactly 2.54 centimeters. That is why there is no simpler round-number conversion: the factor is exact, not rounded. As a quick mental estimate, every inch is a little over two and a half centimeters.

Screens, paper and picture frames

Screen sizes are quoted as the diagonal, and the unit flips depending on where you are reading. A 27-inch monitor is 68.6 cm corner to corner; a 55-inch TV is 139.7 cm; a 6.1-inch phone is 15.5 cm. Because it is a diagonal, you convert the single number directly — there is no need to work out width and height separately.

Paper is the other everyday collision. US Letter is 8.5 × 11 inches, or 21.59 × 27.94 cm. A4 is 21 × 29.7 cm, which is 8.27 × 11.69 inches. They are close enough to look interchangeable and different enough to cause problems: A4 is narrower but noticeably taller, so a document laid out for one will shift or clip when printed on the other. Picture frames have the same trap — a "10 × 8" frame sold in the US is inches, while the same nominal size in Europe is usually a metric size that is a few millimetres off.

Converting height between the two systems

Height is the conversion people look up most, and it needs an extra step because imperial height is written in feet and inches rather than inches alone. Work in total inches first: multiply the feet by 12, add the spare inches, then multiply by 2.54.

So 5 ft 10 in is (5 × 12) + 10 = 70 inches, and 70 × 2.54 = 177.8 cm. Going the other way, divide the centimetres by 2.54 for total inches, then divide by 12 — the whole number is the feet and the remainder is the inches. 180 cm is 70.87 inches, which is 5 ft 10.9 in.

Clothing and body measurements

Size charts routinely mix the two systems, sometimes on the same page. A 32-inch waist is 81.3 cm, a 34-inch chest is 86.4 cm, and a 30-inch inseam is 76.2 cm. Shoe sizing is worse, because much of the world sizes by foot length in centimetres while the US and UK use their own unrelated scales — a 27 cm foot is about 10.6 inches, which is roughly a US men's 9. When a chart gives one unit and your tape measure reads the other, convert the measurement rather than guessing the size across: being an inch out is a whole size, and sizes are not standardised between brands anyway.

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