Inches to CM Converter

Inches are the imperial unit you'll still see on UK TV sizes, monitor specs, clothing measurements and most American-sourced product listings. Centimetres are the metric equivalent used by furniture retailers, IKEA, European clothing sizes and almost every set of assembly instructions.

The formula in plain English: multiply the number of inches by 2.54 and you have the length in centimetres. Since 1959, the inch has been defined as exactly 2.54 cm by international agreement, so this is an exact conversion — not an approximation.

Worked example. You're buying a 55-inch TV and want to know if it fits a media unit that's 130 cm wide. 55 × 2.54 = 139.7 cm. The screen alone is 9.7 cm wider than the unit — and the bezel and stand add more, so it won't fit. A 50-inch TV is 50 × 2.54 = 127 cm — that's the largest size that comfortably fits within 130 cm of usable width.

Why this matters. Most "doesn't fit" disasters in flat-pack furniture, TV mounts and rugs come from comparing two numbers in different units without realising. A "60-inch" TV is not 60 cm — it's 152 cm. A "12-inch" pizza box doesn't fit in a 30 cm cupboard slot because it's 30.5 cm and the box has flaps. Doing the conversion before you buy or drill is the difference between a clean install and an expensive return.

When to use it. TV and monitor sizing, picture-frame fitting, fabric and clothing measurements, comparing US-sized products with UK furniture, and reading any specification that mixes units.

When not to rely on it alone. TV sizes are measured diagonally across the screen, not horizontally — so a 55-inch (139.7 cm diagonal) TV is actually about 122 cm wide and 71 cm tall. Always check the manufacturer's stated width and height, not just the headline inch figure.

Common mistakes. Confusing inches with feet (1 ft = 12 in = 30.48 cm). Reading a fractional inch like 3 ½ as "3.5 inches" but then forgetting to convert — 3.5 × 2.54 = 8.89 cm, not 3.5 cm. Treating the conversion as "× 2.5" for mental maths; that under-counts every measurement by 1.6%.