cm to inches converter

How to convert centimeters to inches

A centimeter is a hundredth of a metre. An inch, since the 1959 international yard and pound agreement, is exactly 25.4 millimetres, which is 2.54 centimetres. Dividing centimetres by 2.54 is the whole conversion. Ten centimetres is 3.937 inches, not 4, and not 3.94 unless you are rounding to two decimals on purpose. The older US survey inch differed only in the sixth digit and is not what a ruler, a CSS pixel story, or a product label means.

People hit this pair for screen sizes that are quoted in inches while a desk is measured in centimetres, for clothing that mixes cm and inches, and for 3D prints whose slicer wants inches. A 27-inch class display is a diagonal, not a width, so convert the number you actually measured.

Exact formula

Formulainches = centimeters ÷ 2.54

inches = centimeters ÷ 2.54 One cm is 0.393700787402 in. Ten cm is 3.93700787402 in. The worked example below uses that same conversion.

Conversion table

The centimeters column runs from 1 cm (0.3937 in) through 300 cm (118.11 in).

Worked example: Centimeters to Inches

A desk edge measured as 10 cm is 3.937 in, and that is not the 4 inches a 2.5 shortcut promises. The definition check is 2.54 cm, which must come out as 1 in because the international inch is exactly 25.4 mm. A person who is 180 cm tall is 70.866 in. Clothing labels mix those centimetres with inch sizes, and a 27-inch class monitor is a diagonal, so convert the length you actually measured. CSS pixels are not this inch.

Pitfalls for centimeters to inches

• Do not divide by 2.5. That is a rough estimate and it is already wrong by more than a millimetre at 10 cm.
• A pixel is not an inch. CSS px is a reference pixel. Physical inches need the display's actual size.
• Nominal lumber sizes (a 'two by four') are not the measured size in either unit.
• The international inch is exact. Rounding 2.54 to 2.5 and then rounding the result again stacks two errors.