How to use it
- Enter the length in inches.
- Read the result in centimeters, or swap the units.
- Pick the decimal places you need.
- For a screen size, enter the diagonal and the aspect ratio.
The formula
cm = inches × 2.54 and inches = cm ÷ 2.54 (or cm × 0.3937).
The 2.54 factor is exact, not rounded. Since the international yard and pound agreement of 1959, one inch has been defined as exactly 25.4 millimeters.
Example: a 15.6-inch laptop screen is 15.6 × 2.54 = 39.62 cm across the diagonal.
Inches to cm chart
| Inches | Centimeters |
|---|---|
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 5 in | 12.7 cm |
| 6 in | 15.24 cm |
| 10 in | 25.4 cm |
| 12 in (1 ft) | 30.48 cm |
| 24 in | 60.96 cm |
| 36 in (1 yd) | 91.44 cm |
Going the other way, 1 cm = 0.3937 in, 10 cm = 3.937 in and 100 cm = 39.37 in.
TV and monitor sizes
Screens are sold by their diagonal in inches, which doesn't tell you how wide the set is. Enter the diagonal and pick the aspect ratio (16:9 for TVs, 21:9 for ultrawide monitors, 16:10 or 3:2 for many laptops, 4:3 for older screens), and the tool shows the width and height in inches and centimeters.
| 16:9 screen | Width | Height |
|---|---|---|
| 32 in | 27.9 in | 15.7 in |
| 50 in | 43.6 in | 24.5 in |
| 55 in | 47.9 in | 27.0 in |
| 65 in | 56.7 in | 31.9 in |
These numbers describe the visible picture. The bezel and stand add a little more, so check the spec sheet before you buy a TV stand or a wall niche.
Common uses
- Clothing sizes: waist and inseam in inches (a 32-inch waist is 81.3 cm).
- Phones and tablets: screen sizes are always quoted in inches.
- Paper: US Letter is 8.5 × 11 in, which is 21.59 × 27.94 cm.
- Wheels and pipes: rim sizes are in inches; pipe sizes are nominal, so use the inches to mm converter with its pipe chart.
Need feet and inches? The height converter handles 5′10″ style values.
Measuring accurately
Most US tape measures show inches divided into sixteenths, while metric rulers show millimeters. When you read a tape in inches, convert the fraction to a decimal first: 5 3/8 in is 5.375 in, which is 13.65 cm. The inches to mm converter has a chart of common fractions such as 1/16, 1/8, 3/16 and 1/4 inch.
Pick the number of decimal places to match how precisely you measured. A measurement taken to the nearest 1/8 inch is only accurate to about 3 mm, so showing four decimals of a centimeter adds false precision. For sewing or woodworking, one decimal place in centimeters (to the millimeter) is usually enough; for machining, work in millimeters with two decimals.
Inch symbols and abbreviations
You'll see inches written as in, ″ (double prime) or a straight " quote mark, and feet as ft, ′ or '. So 5′ 6″ means 5 feet 6 inches, which is 66 inches or 167.6 cm. The converter accepts plain numbers; type 66 for 66 inches.
Frequently asked questions
How many cm is 1 inch?
Exactly 2.54 centimeters.
How do I convert cm to inches?
Divide by 2.54, or multiply by 0.3937. For example, 30 cm is 11.81 inches.
How wide is a 65-inch TV?
A 65-inch 16:9 TV has a picture about 56.7 inches (144 cm) wide and 31.9 inches (81 cm) tall. The whole set is slightly larger because of the bezel.
Is the TV size measured diagonally?
Yes. TV and monitor sizes are the diagonal of the visible screen, corner to corner.
How many inches is 100 cm?
100 cm is 39.37 inches, or 3 feet 3.37 inches.
Last updated: November 12, 2026