Inches to centimeters converter
Convertersconversion pair
Convert inches to centimeters instantly: 1 inch is exactly 2.54 cm. The official math, every other unit still on screen, and one-click copying.
An inch is exactly 2.54 cm — the one number both measuring worlds signed.
work surface
Math, not advice — results are indicative. Read the disclaimer.
pro tips
Mental shortcut: multiply by 2.5, then nudge up slightly. 20 in ≈ 51 cm; the exact answer is 50.8.
A 55-inch TV measures 139.7 cm diagonally — check the wall before you fall in love with it.
A half-inch wrench is 1.27 cm across; metric sockets are always a hair off, which is how bolts end up rounded.
what it does
One inch is exactly 2.54 centimeters. Not roughly, not about — exactly, by treaty since 1959. Multiply inches by 2.54 and you get centimeters with the confidence of someone quoting international law at a dinner party.
Where it shows up: TV screens sold in inches to people whose walls are in centimeters, wrench sets where metric and imperial sockets look at each other suspiciously, height charts, and every online order where the size guide and your tape measure refuse to speak the same language.
The rough version: multiply inches by 2.5 and add a little extra — 20 inches becomes "about 51 cm" when the true answer is 50.8. For anything that isn't load-bearing or a wedding dress, that's plenty.
Type any number and the widget answers in centimeters on the spot, with the math written in the hint. Click the result to copy it, and use the swap button when the conversation flips back the other way — the centimeters-to-inches version lives one click away.
quick answers
How many centimeters is one inch?
Exactly 2.54 cm — defined that way since 1959, so this is one of the few conversions with no rounding drama attached.
Is 10 inches the same as 25 cm?
Almost — 10 inches is 25.4 cm. The missing 0.4 is small enough for furniture shopping and big enough for engineering.
How wide is a 55-inch TV in centimeters?
The diagonal is 139.7 cm. The actual width depends on the shape of the screen, but the wall should budget for about 122 cm on a modern 16:9 panel.
Why is the conversion such a clean number?
Because the inch was redefined to make it clean: in 1959 the yard was locked to 0.9144 meters, which makes one inch exactly 2.54 cm. Clean numbers are what happens when committees agree.