How do I convert cm to inches?

Divide the centimeter value by 2.54. One inch is defined as exactly 2.54 centimeters, so 100 cm ÷ 2.54 = 39.37 inches. To go the other way, multiply inches by 2.54. The converter does both directions for you — type in either field and the other updates instantly.

How many inches is 170 cm?

170 cm is about 66.93 inches, which is 5 feet 6.9 inches — a common question for body height. 180 cm is about 70.87 inches (5 ft 10.9 in). For any other height, just type the centimeter value into the converter.

Is the 2.54 factor exact or rounded?

Exact. Since the international yard and pound agreement of 1959, the inch is defined as exactly 25.4 millimeters — so 2.54 cm per inch is a definition, not an approximation. Any rounding in results comes only from trimming long decimals for readability.

Is this converter free and private?

Yes. The maths runs entirely in your browser with plain JavaScript — nothing you type is uploaded, stored or shared, there's no account and no usage limit. It also keeps working offline once the page has loaded.

Converters

CM to Inches Converter

Convert centimeters to inches (and back) instantly — with common values, the exact formula and a reference table.

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Common values

Centimeters

Inches

Type in either field — the other converts live. 1 inch = 2.54 cm exactly.

Result

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Enter a value in Centimeters or Inches

How the conversion works

The inch is defined as exactly 2.54 centimeters, so the conversion is a single division or multiplication:

cm → inches: divide by 2.54 — 100 cm ÷ 2.54 = 39.3701 in
inches → cm: multiply by 2.54 — 12 in × 2.54 = 30.48 cm

There is no rounding hidden in the factor itself: 2.54 is a definition (fixed internationally in 1959), so results are as exact as the number of decimals you keep.

Quick reference table

Centimeters	Inches
1 cm	0.39 in
5 cm	1.97 in
10 cm	3.94 in
20 cm	7.87 in
30 cm	11.81 in
50 cm	19.69 in
100 cm	39.37 in
160 cm	62.99 in (5 ft 3 in)
170 cm	66.93 in (5 ft 6.9 in)
180 cm	70.87 in (5 ft 10.9 in)

How to use it

Type a value into either field — centimeters or inches.
The other side converts live; results are trimmed to four decimals.
Tap a common value chip (10, 30, 50, 100, 170, 180 cm) to start from a typical measurement.
Copy puts the full conversion (e.g. 170 cm = 66.9291 in) on your clipboard.

When you need this

Screen sizes, furniture from international shops, body height on forms, sewing patterns, paper formats — anything that crosses between metric and imperial worlds. For lengths in other units, the Feet to Meters Converter and Miles to KM Converter work exactly the same way, and the general Unit Converter covers weight, volume, temperature and more in one place.

Private by design

The conversion runs in your browser — nothing is uploaded or tracked, and there's no sign-up. Browse more free utilities on the all tools page.

Frequently asked questions

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