Centimeters to Inches
Convert centimeter to inch instantly — type a value and read the result, with the exact formula shown.
Example
1 cm = 0.3937008 in, 5 cm = 1.968504 in, 10 cm = 3.937008 in.
How it works
Inch = Centimeter × 0.3937008. Every value is converted through a single meter base unit using internationally defined conversion factors, so any from/to pair stays consistent.
Good to know
Converting centimeters to inches is something you do constantly once you realize how much of the world is split between the two systems. A European furniture listing gives a sofa as 220 cm wide, but your American doorway is measured in inches; a clothing size chart shows a 96 cm chest while the shirt tag reads in inches; a TV diagonal, a phone screen, a piece of luggage, or a wound measured by a doctor all routinely need this swap. It is the single most common "metric to my ruler" conversion for anyone working across borders.
The centimeter is a metric unit, one-hundredth of a meter, which since 1983 is defined by the distance light travels in a vacuum. The inch is an imperial and US customary unit, and since 1959 it has been pinned to the metric system by international agreement at exactly 2.54 cm. That fixed definition is why this is one of the few cross-system conversions that is genuinely exact rather than an approximation, and it means 1 cm equals 1 divided by 2.54, or about 0.3937 inch.
For mental math, here are two shortcuts worth memorizing:
- To go from cm to inches, multiply by 0.4 and shave off a hair — so 50 cm is roughly 20 inches (the exact answer is 19.7), and 100 cm is about 39.4 inches.
- A handy anchor is that 2.5 cm is almost exactly 1 inch, so a quick "divide by 2.5" gets you close, and 30 cm is very nearly 1 foot (it is actually 11.81 inches).
The most common mistake is mixing up direction — multiplying by 2.54 when you should divide, which inflates a result instead of shrinking it. Remember that an inch is the bigger unit, so any length expressed in inches should be a smaller number than the same length in centimeters. Also watch the precision trap: rounding 0.3937 to a flat 0.4 introduces about a 1.6% error, which is invisible for a bookshelf but adds up fast over long runs like fabric, trim, or piping, where you should keep the full factor.
Frequently asked questions
How do you convert centimeter to inch?
Multiply the number of centimeters by 0.3937008 to get inches. For example, 1 cm = 0.3937008 in.
What is 1 centimeter in inches?
1 centimeter equals 0.3937008 inches (1 cm = 0.3937008 in).
How many centimeters are in 1 inch?
There are 2.54 centimeters in 1 inch.
Is this converter free and private?
Yes. It runs entirely in your browser, so your inputs never leave your device, there is no sign-up, and it works offline once loaded.
Are the conversions exact?
Conversions use internationally defined factors and are exact where the definitions are exact (for example, 1 inch = 2.54 cm). Displayed results are rounded for readability.
People also ask
How many inches is 170 cm?
170 cm equals about 66.93 inches, which is 5 feet 7 inches — a common height conversion. The exact math is 170 divided by 2.54.
What is 10 cm in inches?
10 cm is 3.937 inches, just under 4 inches. A quick estimate is 10 times 0.4, which gives 4 and is only about 1.6% high.
Is 2.54 the number to multiply or divide by?
Divide centimeters by 2.54 to get inches, or equivalently multiply by 0.3937. You only multiply by 2.54 when going the other way, from inches to centimeters.
How do I convert cm to inches and feet for height?
First divide the centimeters by 2.54 to get total inches, then divide that by 12 for feet and keep the remainder as inches. For example, 180 cm is 70.87 inches, which is 5 feet 10.9 inches.
How many cm is a 1 inch?
1 inch is exactly 2.54 cm by international definition. This value is exact, not rounded, so it works as a precise anchor for any conversion.
What is 15 cm in inches?
15 cm equals 5.91 inches, just shy of 6 inches. A 15 cm ruler is the standard pocket size and is roughly half a foot.
Why isn't there a clean whole number for cm to inches?
Because the two units are defined on different bases — 1 inch is fixed at exactly 2.54 cm, so the reverse, 1 cm in inches, is the messy fraction 0.3937. The clean number lives on the inch-to-cm side.
How accurate is using 0.4 as a shortcut for cm to inches?
Multiplying by 0.4 instead of 0.3937 overstates the result by about 1.6%, so 200 cm comes out as 80 inches instead of the true 78.7. It is fine for rough estimates but not for cutting material or precise measurements.
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