Inches to Centimeters Calculator

There are exactly 2.54 centimeters in one inch. That conversion factor has been fixed by international agreement since 1959 and is the same in the US, UK, Canada, and Australia.

1 inch is exactly 2.54 cm, which is also 25.4 mm or 0.0254 m. The calculator returns all three metric equivalents at once so you can pick the unit that fits your context.

Multiply your inch value by 2.54. For a quick mental shortcut, multiply by 2.5 then add 1.6% of the result - that gets you within rounding error for most everyday measurements. Example: 10 inches x 2.54 = 25.4 cm.

Divide centimeters by 2.54. For a rough mental check, divide by 2.5 and shave off about 1.6%. Example: 100 cm / 2.54 = 39.3701 inches, which the calculator rounds to 4 decimal places.

Yes. The international inch (2.54 cm exactly) has been the standard in all major English-speaking countries since 1959. The old US Survey inch was 2.540005... cm - a tiny difference used only in legacy land-survey work, not in everyday or engineering contexts.

5 feet 9 inches is 69 total inches. Multiply by 2.54 to get 175.26 cm. To convert any height, first convert feet to inches (multiply by 12), add the remaining inches, then multiply the total by 2.54.

Metric units use powers of 10, so moving between millimeters, centimeters, and meters is simple arithmetic. They are standard in science, medicine, and international trade and the primary everyday system in most countries. The US retains customary units in many daily uses.