Inch to CM Converter – Inches to Centimeters and Back
Inch to CM Converter
Convert area or length dimensions instantly with exact global scaling metrics
Quick answer
To convert inch to cm, multiply the inches by 2.54. One inch is exactly 2.54 centimeters, so 12 in × 2.54 = 30.48 cm. To go from centimeters to inches, divide by 2.54: 100 cm ÷ 2.54 = 39.3701 in.
Our free Inch to CM Converter does the multiplication for you and shows the exact formula with your number. Switch to CM to Inches with one click when you need the reverse. It is useful for screen sizes, clothing measurements, paper and photo sizes, woodworking and school projects.
Why Is One Inch Exactly 2.54 cm?
In 1959 the United States, the United Kingdom and other Commonwealth countries agreed on the international yard, which fixed the inch at exactly 25.4 millimeters, or 2.54 centimeters. Before that, the US and UK inches differed very slightly. Because the factor is now exact, an inch to cm conversion has no rounding error of its own. Any rounding comes only from how many decimals you display.
Inch to CM Formula
| Conversion | Formula | Example |
|---|---|---|
| Inches to centimeters | cm = in × 2.54 | 12 in = 30.48 cm |
| Centimeters to inches | in = cm ÷ 2.54 | 30 cm = 11.811 in |
| Inches to millimeters | mm = in × 25.4 | 0.5 in = 12.7 mm |
| Feet and inches to cm | cm = (ft × 12 + in) × 2.54 | 5 ft 4 in = 162.56 cm |
How to Use the Inch to CM Converter
The tool sits at the top of this page. Follow these four steps.
Step 1: Choose Inches to CM or CM to Inches
Click Inches to CM to convert inches, or CM to Inches for the reverse. The label and unit badge update to match. We keep Inches to CM selected.
Step 2: Enter the Length in Inches
Type your measurement into the box. Decimals work, so 0.75 for three quarters of an inch is fine. In our example we enter 12 inches, the length of a standard ruler.
Step 3: Click Convert Length
Press Convert Length. If the box is empty or holds a negative number, the tool asks for a valid value instead of showing a result.
Step 4: Read the Result in Centimeters
The highlighted box shows 30.48 cm. Below it you can see the constant (1 inch = 2.54 cm) and the formula with your number plugged in, so the result is easy to double-check.
Inch to CM Conversion Chart
| Inches | Centimeters |
|---|---|
| 0.25 in | 0.635 cm |
| 0.5 in | 1.27 cm |
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 4 in | 10.16 cm |
| 5 in | 12.7 cm |
| 6 in | 15.24 cm |
| 8 in | 20.32 cm |
| 10 in | 25.4 cm |
| 12 in | 30.48 cm |
| 15 in | 38.1 cm |
| 18 in | 45.72 cm |
| 24 in | 60.96 cm |
| 36 in | 91.44 cm |
CM to Inches Chart
| Centimeters | Inches |
|---|---|
| 1 cm | 0.3937 in |
| 5 cm | 1.9685 in |
| 10 cm | 3.937 in |
| 15 cm | 5.9055 in |
| 20 cm | 7.874 in |
| 25 cm | 9.8425 in |
| 30 cm | 11.811 in |
| 50 cm | 19.685 in |
| 100 cm | 39.3701 in |
Fractional Inches to CM and MM
Tape measures, drill bits and bolts often use fractions. Turn the fraction into a decimal first (for example 3/8 = 0.375), then use the inch to cm tool.
| Fraction | Decimal inch | Centimeters | Millimeters |
|---|---|---|---|
| 1/16 in | 0.0625 | 0.1588 cm | 1.5875 mm |
| 1/8 in | 0.125 | 0.3175 cm | 3.175 mm |
| 1/4 in | 0.25 | 0.635 cm | 6.35 mm |
| 3/8 in | 0.375 | 0.9525 cm | 9.525 mm |
| 1/2 in | 0.5 | 1.27 cm | 12.7 mm |
| 5/8 in | 0.625 | 1.5875 cm | 15.875 mm |
| 3/4 in | 0.75 | 1.905 cm | 19.05 mm |
| 7/8 in | 0.875 | 2.2225 cm | 22.225 mm |
Screen Sizes in Inches and CM
TV, monitor and phone sizes are measured diagonally across the screen, in inches. Here is what common sizes mean in centimeters:
| Screen size | Diagonal in cm |
|---|---|
| 24 in monitor | 60.96 cm |
| 32 in TV | 81.28 cm |
| 40 in TV | 101.6 cm |
| 43 in TV | 109.22 cm |
| 50 in TV | 127 cm |
| 55 in TV | 139.7 cm |
| 65 in TV | 165.1 cm |
Common Mistakes When Converting Inches to CM
- Dividing instead of multiplying. Centimeters are smaller than inches, so the number in cm must always be bigger. If it got smaller, you divided by mistake.
- Using 2.5 as the factor. It is close for small values, but for 65 inches it gives 162.5 cm instead of 165.1 cm.
- Confusing the inch symbol. 5′ 4″ means 5 feet 4 inches, not 5.4 inches. Convert it as (5 × 12 + 4) × 2.54.
- Converting area with the length factor. Square inches to square centimeters uses 2.54² = 6.4516.
Who Uses an Inch to CM Converter?
Online shoppers comparing TV sizes and clothing measurements, tailors and crafters working from patterns, carpenters reading imperial plans, photographers choosing print sizes, and students doing unit homework. For heights, try our cm to feet converter, which also shows feet and inches.
Frequently Asked Questions
How do I convert inch to cm?
Multiply the number of inches by 2.54. For example, 12 in × 2.54 = 30.48 cm.
How many cm is 1 inch?
One inch is exactly 2.54 centimeters, or 25.4 millimeters.
How do I convert cm to inches?
Divide the centimeters by 2.54. For example, 30 cm ÷ 2.54 = 11.811 inches.
How many inches is 100 cm?
100 cm is 39.3701 inches, or about 3 feet 3.37 inches.
What is a 55 inch TV in cm?
A 55 inch TV has a diagonal of 139.7 cm. TV sizes are always measured corner to corner, not across the width.
Can I enter fractions like 3/4 inch?
Enter the decimal form instead. 3/4 is 0.75, so type 0.75 to get 1.905 cm.
Is this inch to cm converter free?
Yes. It is free, needs no sign-up, and runs entirely in your browser.