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Length

Centimeters to Inches Converter

Convert metric lengths in centimeters to inches for measurements, specifications, printing, and everyday comparisons.

Instant resultAdjustable assumptionsNo data sent
Instant conversion

cm in

Runs in your browser
inches1in

Result rounded to a maximum of six decimal places.

Conversion ruleinches = cm ÷ 2.54

2.54 cm = exactly 1 inch.

01
Method

How to convert centimeters to inches

Divide centimeters by 2.54. One international inch is defined as exactly 2.54 centimeters.

Formulainches = cm ÷ 2.54

2.54 cm = exactly 1 inch.

02
Worked example

Convert 30 cm to in

Apply the conversion rule to 30 centimeters. Using the default settings, the result is 11.811024 in.

30 cm11.811024 in
03
Quick reference

cm to in conversion table

These pre-calculated values use the same formula and default settings as the converter above.

Common centimeters to inches conversions
centimeters (cm)inches (in)
1 cm0.393701 in
2.54 cm1 in
5 cm1.968504 in
10 cm3.937008 in
20 cm7.874016 in
25 cm9.84252 in
30 cm11.811024 in
50 cm19.685039 in
75 cm29.527559 in
100 cm39.370079 in
150 cm59.055118 in
200 cm78.740157 in
04
Practical use

Code and calculation snippets

Reuse the same conversion in a stylesheet or application. Keep contextual font sizes configurable when working with relative CSS units.

JavaScript
const inches = centimeters / 2.54;
Python
inches = centimeters / 2.54
05
Interpretation

Using the result accurately

Use the number of decimal places appropriate for the original measurement. Extra displayed precision cannot make an imprecise measurement more accurate.

Important limitation

This is a linear unit conversion. The output does not account for measurement tolerance, rounding in the source value, or device calibration.

Reference: NIST Guide to the SI: conversion factors.

Common questions

Centimeters to Inches Converter FAQ

Short answers about the formula, assumptions, and displayed precision.

How do I convert centimeters to inches?

Divide centimeters by 2.54. One international inch is defined as exactly 2.54 centimeters. For example, 30 cm converts to 11.811024 in using the default settings.

What formula does this cm-to-in converter use?

inches = cm ÷ 2.54. 2.54 cm = exactly 1 inch.

What assumptions does the calculator make?

The converter uses the fixed relationship described in the formula: 2.54 cm = exactly 1 inch.

How many decimal places should I use?

The calculator shows up to six decimal places and removes unnecessary trailing zeros. Keep more precision for further calculations, then round the final value to suit your measurement or design system.