Convert inches to cm

1 inch = 2.54 cm, exactly

To convert inches to cm, multiply by 2.54: cm = inches × 2.54. A 55-inch TV has a diagonal of 55 × 2.54 = 139.7 cm. The factor is not rounded: the inch has been defined as 2.54 cm since 1959.

The converter works as you type and shows the formula 1 in = 2.54 cm. For a fraction, enter its decimal value: 0.75 for 3/4 in. The table underneath also gives the length in millimeters and meters, handy for a European order form or a sewing pattern.

Inches to cm conversion chart

The diagonal is not the width

A screen size is its diagonal. To know whether it fits a wall or a stand measured in centimeters, you need the width. On a 16:9 screen, width ≈ 0.8716 × diagonal and height ≈ 0.4903 × diagonal:

• 43 in: 95.19 cm wide, 53.55 cm high;
• 55 in: 121.76 cm wide, 68.49 cm high;
• 65 in: 143.90 cm wide, 80.94 cm high.

These figures cover the picture only. Add the bezel and the stand.

Height, bikes, kitchen, plumbing

• Height in feet and inches: turn everything into inches first. 5 ft 9 in is 5 × 12 + 9 = 69 in, so 69 × 2.54 = 175.26 cm.
• Bike wheels and rims: 26, 27.5 and 29 in are 66.04, 69.85 and 73.66 cm, tire included. A 17-inch car rim is 43.18 cm.
• Pizzas and pans: a 12-inch pizza is 30.48 cm across, a 10-inch skillet 25.4 cm.
• Pipes: 1/2 in = 1.27 cm and 3/4 in = 1.905 cm, but pipe sizes are nominal. A 1/2-inch pipe has an outside diameter of 0.840 in, which is 2.13 cm. Measure before ordering metric parts.

Doing it in your head

Multiply by 10, then divide by 4, which is the same as multiplying by 2.5. For 32 in: 320 ÷ 4 = 80 cm, against an exact 81.28 cm. The shortcut comes out 1.6% low. Add 1.6 cm for every 100 cm you got and you land on the exact figure: 80 + 1.28 = 81.28.

Frequently asked questions

How many cm is a 55-inch TV?

139.7 cm on the diagonal. In 16:9, the picture is 121.76 cm by 68.49 cm.

How do I convert a fraction of an inch?

Divide first: 5/8 = 0.625. Then multiply: 0.625 × 2.54 = 1.5875 cm, or 15.875 mm.

How wide is a 75-inch TV in cm?

The diagonal is 190.5 cm and the picture is 166.04 cm wide by 93.39 cm high.