CM to Inches Converter
Type a length in any unit, like 170 cm, 5'7" or 3 1/4 in, and this free converter shows it in inches, centimeters, millimeters, feet and inches, meters and yards at once. One inch is exactly 2.54 cm, so 10 cm is 3.937 inches, which reads as 3 15/16 on a tape measure.
3 15/16 in
= 3.937 in
Rounded to the nearest 1/16 inch: 0.01 mm over
What is a cm to inches converter?
It turns a length in centimeters into inches, and any length into every other common unit, at once. One inch is exactly 2.54 cm, so the decimal is easy. The part most converters skip is the one you need with a tape measure in your hand: the fraction.
| Centimeters | Inches (decimal) | On a tape measure (1/16) |
|---|---|---|
| 1 cm | 0.394 in | 3/8 in |
| 2.5 cm | 0.984 in | 1 in |
| 5 cm | 1.969 in | 1 15/16 in |
| 10 cm | 3.937 in | 3 15/16 in |
| 20 cm | 7.874 in | 7 7/8 in |
| 30 cm | 11.811 in | 11 13/16 in |
| 50 cm | 19.685 in | 19 11/16 in |
| 100 cm | 39.37 in | 39 3/8 in |
How do you use it?
Type the length with its unit. 170 cm, 25 mm, 1.8 m, 5'7" and 3 1/4 in all work. A plain number uses the unit you pick next to the box.
Pick the precision. Choose how fine the fraction is, from 1/2 inch to 1/64 inch. Most tape measures are marked in sixteenths, so 1/16 is the default.
Read the result. The fraction, the decimal, the feet and inches, and every other unit update together.
What does it show that a quick converter doesn't?
Three things you would otherwise work out by hand. First, the tape-measure fraction at the precision you choose, not a decimal you cannot find on a ruler. Second, the rounding gap in millimeters: 5 cm becomes 1 15/16 in, which is 0.79 mm short, so you know when sixteenths are close enough. Third, a zoomed ruler with inches above and centimeters below, marking where your length falls between the ticks. It also reads compound lengths like 5 ft 7 in or 1 m 20 cm, which a search-box converter does not.
How do you convert height from cm to feet and inches?
Divide by 2.54 for inches, then by 12: the whole number is feet and the rest is inches.
| Height | Inches | Feet and inches (nearest inch) |
|---|---|---|
| 150 cm | 59.06 in | 4 ft 11 in |
| 160 cm | 62.99 in | 5 ft 3 in |
| 170 cm | 66.93 in | 5 ft 7 in |
| 180 cm | 70.87 in | 5 ft 11 in |
| 190 cm | 74.80 in | 6 ft 3 in |
What doesn't this converter do?
It doesn't draw a ruler at actual size, because a screen pixel has no fixed physical size; that needs calibrating the screen first. It doesn't convert pixels or points, which only become inches once you choose a resolution. It doesn't add or subtract measurements. And it uses the international foot, exactly 0.3048 m, not the US survey foot that NIST retired at the end of 2022.
Why is an inch exactly 2.54 cm?
Because six countries, the United States, the United Kingdom, Canada, Australia, New Zealand and South Africa, agreed in 1959 that a yard is exactly 0.9144 meters. A yard is 36 inches, so an inch became exactly 25.4 mm. Every conversion on this page follows from that one number, with no rounding until the result is shown.
Frequently asked questions
How do I convert cm to inches?
Divide the centimeters by 2.54. So 10 cm is 10 ÷ 2.54 = 3.937 inches, and 30 cm is 11.811 inches. To go from inches to centimeters, multiply by 2.54 instead. This converter does both directions from one box: type the number with its unit, and every other unit updates as you type.
How do I convert cm to inches as a fraction?
Convert to decimal inches first, then multiply the part after the point by 16 and round. For 10 cm: 3.937 inches, 0.937 × 16 = 15, so it reads 3 15/16 on a tape measure. This converter does that for you at 1/2 to 1/64 precision and shows how far the fraction is from the real length.
How tall is 170 cm in feet and inches?
170 cm is 66.93 inches, which is 5 feet 6.93 inches, or 5 ft 7 in rounded to the nearest inch. At tape-measure precision it is 5 ft 6 15/16 in. To work it out, divide the centimeters by 2.54 to get inches, then divide by 12: the whole number is feet and the rest is inches.
How many millimeters are in an inch?
Exactly 25.4 millimeters. To convert mm to inches, divide by 25.4, so 10 mm is 0.394 inches, about 3/8 of an inch on a ruler marked in sixteenths. This converter reads mm, cm, m and km as well as inches, feet and yards, so a drawing in millimeters converts as easily as a height in centimeters.
Why is an inch exactly 2.54 cm?
Because of the international yard and pound agreement of 1959. The United States, the United Kingdom, Canada, Australia, New Zealand and South Africa agreed that one yard is exactly 0.9144 meters, which makes one inch exactly 2.54 centimeters. Before that, the American and British inches differed by a few parts per million.
How accurate is the fraction on a tape measure?
A fraction rounded to the nearest 1/16 inch can be off by up to 0.79 mm, and one rounded to 1/64 by up to 0.2 mm. This converter shows the exact gap for your number, such as 0.79 mm short, so you can decide whether 1/16 is close enough or you need a finer mark.
Is the ruler on this page actual size?
No. It is one inch, zoomed in, with the centimeter scale below it, so you can see where your length falls between the marks. A screen pixel has no fixed physical size, since it depends on the display and the zoom, so a page cannot draw a true-size ruler without calibrating it first.
Does this converter use the US survey foot?
No. It uses the international foot, exactly 0.3048 meters. The US survey foot, slightly longer at 1200/3937 meters, was used for land surveying until NIST retired it on December 31, 2022. The difference is about 2 parts per million, which only matters for surveying over long distances, never for a tape measure.
Can I type feet and inches together?
Yes. Type 5'7", 5 ft 7 in, 5 feet 7 inches or even 5' 7 1/2", and the converter adds them up before converting. It also reads mixed metric like 1 m 20 cm. A plain number with no unit uses the unit you pick next to the box, which starts as centimeters.
Can it convert pixels to inches or add measurements?
No. Pixels only become inches once you choose a resolution in dots per inch, which is a question for an image or print tool rather than a length converter. It also does not add or subtract measurements like 5 ft 7 in plus 3 1/4 in; it converts one length at a time, exactly.
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Built and tested by the ÆON Toolhub team. Last updated: October 13, 2026. How we test our tools