CM to Inches Converter – Centimetres to Inches and Back

How to use the cm to inches converter

1. Choose the direction: cm → in or in → cm.
2. Type the value.

The result appears instantly, along with feet and inches and millimetres. The table below shows common lengths from 1 cm to 180 cm.

The formulas

Worked examples

• 30 cm = 30 ÷ 2.54 = 11.81 in
• 10 in = 10 × 2.54 = 25.4 cm
• 175 cm = 68.9 in = 5 ft 8.9 in
• 6 ft = 72 in = 182.88 cm

Common conversions

Where you’ll need it

• Heights: doctors and forms in the US use feet and inches; most other countries use centimetres.
• Screens: TVs, monitors and phones are measured diagonally in inches.
• Clothing: waist and inside-leg measurements, often in inches even in metric countries.
• DIY and furniture: imported furniture and tools may be measured in either system.
• Paper and photos: a 4 × 6 inch photo is 10.16 × 15.24 cm.
• School and science: metric is the standard in science everywhere.

Measuring tips

• Measure twice, and use a tape with both scales to avoid converting at all.
• For body measurements, keep the tape level and snug, not tight.
• When buying online from another country, check whether a size chart is in inches or centimetres before you compare.

Fractions of an inch

Rulers and tape measures in the US mark inches in fractions — halves, quarters, eighths and sixteenths — rather than decimals. To turn a decimal inch into the nearest sixteenth, multiply the decimal part by 16 and round: 11.81 inches is 11 inches plus 0.81 × 16 ≈ 13, so about 11 13/16 inches. Going the other way, 5/8 inch is 0.625 inch, which is 0.625 × 2.54 = 1.59 cm. Woodworkers and engineers who need precision often switch to millimetres for this reason: 1/16 inch is about 1.6 mm, so a millimetre scale is finer than most fractional rulers.

Common mistakes

• Mixing up the direction. If the answer is bigger than the number you started with, check: inches are always the smaller number for the same length.
• Rounding too early. Round only the final answer, especially when converting several measurements for a pattern or a cut list.
• Forgetting the 12. 5.5 feet is 5 feet 6 inches, not 5 feet 5 inches.

A short history of the inch

The inch was once defined differently in different countries — based on barleycorns or the width of a thumb. In 1959 the United States, the United Kingdom and other Commonwealth countries agreed on the international inch of exactly 25.4 millimetres. That’s why the conversion factor 2.54 is exact, with no rounding.

For other units, try the feet to metres converter, the kg to lbs converter and the all-in-one unit converter. For shoe sizes from foot length, see the shoe size converter.