Inches to cm

The exact conversion

Inches to centimeters is the conversion behind TV sizes, monitor diagonals, tire sidewalls, and height written as feet and inches. The inch is exactly 2.54 centimeters, so a foot, which is 12 inches, is exactly 30.48 centimeters. A 55-inch screen is a 55-inch diagonal, not the width: 55 × 2.54 = 139.7 centimeters from corner to corner of the panel, frame not included.

The formula used above is cm = in × 2.54. Both boxes stay in step, so you can start from either unit. Results are rounded for display; the factor itself is the legal definition, not a rounded shortcut.

Worked examples

Each line is the same formula with a new starting number. You can match it against the converter by typing the value on the left.

• 1 inch: 1 × 2.54 = 2.54 centimeters.
• 12 inches: 12 × 2.54 = 30.48 centimeters.
• 55 inches: 55 × 2.54 = 139.7 centimeters.

Where the rounding matters

To convert a height such as 5 feet 10 inches, turn it into inches first. Five feet is 60 inches, plus 10 is 70 inches. Then 70 × 2.54 = 177.8 centimeters. Six feet is 72 × 2.54 = 182.88 centimeters, usually written 183 cm. For a piece of furniture, keep the tenth of a centimeter; for a conversation about height, the whole centimeter is enough.

Multiplying by 2.5 instead of 2.54 drops 1.6%. On a 65-inch television that is more than 2.5 centimeters of diagonal, enough to matter if you are checking whether the set fits a cabinet. Also remember that a screen size is the diagonal of the display, measured corner to corner, not the width of the stand.

Conversion table: inches to cm