12 in to cm
- Inches (in)
- 12 in
- Centimeters
- 30.48 cm
Checked against: Exact-fraction computation from the legal unit definitions
Inches to centimeters converter
Convert inches to centimeters (inches to cm) with the exact factor, a conversion chart and worked steps.
By AdminDrafted with AI writing toolsUpdated Checked examples: 3
Centimeters
cm
Centimeters: 30.48 cm
- Conversion
- 12 in = 30.48 cm
- 1 cm in inches
- 0.3937007874in
12 in is about 30.48 cm. In the other direction, 1 cm ≈ 0.39370079 in.
Inches to centimeters
Inches to cm chart
| Inches | Centimeters |
|---|---|
| 0.25 | 0.635 |
| 0.5 | 1.27 |
| 0.75 | 1.905 |
| 1 | 2.54 |
| 2 | 5.08 |
| 4 | 10.16 |
| 6 | 15.24 |
| 8 | 20.32 |
| 12 | 30.48 |
| 24 | 60.96 |
| 36 | 91.44 |
| 48 | 121.92 |
| 72 | 182.88 |
How it's calculated S
Conversion factor
Exact by definition.
Multiply
About the inches to centimeters converter
To convert inches to centimeters, multiply by 2.54; to convert back, multiply by 0.3937007874. For example, 12 in is about 30.48 cm. Displayed factors and results may be rounded.
Inch dimensions on a product listing may include fractions such as a half or a quarter. Enter a decimal or fraction for the full inch measurement before converting. Do not read 5 ft 6 in as 5.6 in, or confuse a screen's diagonal with its width.
The 1959 international yard and pound agreement defines the inch exactly: 1 in = 25.4 mm.
Both units are defined exactly. Calculations use 50 significant digits and round only for display.
How to convert inches to cm
Multiply inches by 2.54. The inch is defined as exactly 2.54 cm, so the answer is exact: 6 in = 15.24 cm, 10 in = 25.4 cm and 40 in = 101.6 cm. Fractions work the same way once written as decimals: 6 1/2 in = 6.5 × 2.54 = 16.51 cm.
NIST's conversion tables give the inch as exactly 0.0254 m, which is where the 2.54 comes from.
Inches to centimeters chart
Every value below is exact.
| Inches (in) | Centimeters (exact) |
|---|---|
| 1 | 2.54 |
| 3 | 7.62 |
| 4 | 10.16 |
| 5 | 12.70 |
| 6 | 15.24 |
| 7 | 17.78 |
| 8 | 20.32 |
| 9 | 22.86 |
| 10 | 25.40 |
| 12 | 30.48 |
| 15 | 38.10 |
| 17 | 43.18 |
| 18 | 45.72 |
| 21 | 53.34 |
| 23 | 58.42 |
| 24 | 60.96 |
| 30 | 76.20 |
| 32 | 81.28 |
| 45 | 114.30 |
| 70 | 177.80 |
| 85 | 215.90 |
| 90 | 228.60 |
Multiplying by 2.54 in your head
Split 2.54 into 2 + 0.5 + 0.04, multiply each part and add. For 8 inches: 16 + 4 + 0.32 = 20.32 cm. For 17 inches: 34 + 8.5 + 0.68 = 43.18 cm. The result is the exact product, not an estimate.
Fractions of an inch
US tape measures and product specs use halves, quarters, eighths and sixteenths:
- 1/2 in = 1.27 cm
- 1/4 in = 0.635 cm
- 1/8 in = 0.3175 cm
- 1/16 in = 0.15875 cm, about 1.6 mm
For a mixed number, add the fraction to the whole inches first: 5 3/4 in is 5.75 in, or 14.605 cm.
US product dimensions
Furniture, luggage and appliances sold in the US are usually listed in inches. Convert each dimension on its own: a carry-on limit of 22 × 14 × 9 inches is 55.88 × 35.56 × 22.86 cm. A suitcase listed as 56 cm tall is 0.12 cm over the 22-inch limit.
TV and monitor sizes are diagonals. A 32-inch screen measures 81.28 cm corner to corner and a 40-inch screen 101.6 cm. For its width and height, use the screen size calculator with the screen's resolution.
Common mistakes
- Reading 5 3/4 as 5.34. 5 3/4 in is 14.605 cm, while 5.34 in is 13.5636 cm.
- Typing feet and inches as one number. 5 ft 11 in is 71 inches, or 180.34 cm. 5.11 inches is only 12.9794 cm. For heights, use feet to cm or the height converter.
- Dividing by 2.54. That is the cm-to-inches direction. A centimeter is smaller than an inch, so the cm figure must come out larger.
- Using 2.54 on square inches. Multiply by 2.54², which is 6.4516: 80 in² = 516.128 cm². The area converter handles other square units.
Related converters
For the opposite direction, use cm to inches. For very small parts, inches to mm lists common fractions in millimeters.
Worked examples
2 in to cm
- Inches (in)
- 2 in
- Centimeters
- 5.08 cm
Checked against: Exact-fraction computation from the legal unit definitions
48 in to cm
- Inches (in)
- 48 in
- Centimeters
- 121.92 cm
Checked against: Exact-fraction computation from the legal unit definitions
Questions
How many centimeters are in one inch?
1 in is about 2.54 cm. The 1959 international yard and pound agreement defines the inch exactly: 1 in = 25.4 mm.
How do I convert inches to centimeters?
Multiply by 2.54: 12 in × 2.54 ≈ 30.48 cm. To convert back, divide by the same factor. The factor shown may be rounded.
How can I estimate inches in centimeters without a calculator?
Multiply by 2.5. This is 1.6% below the exact factor (about 2.54), so 12 in comes out as 30 cm instead of 30.48 cm.
About this calculator
Sources
Checked against references
This calculator includes 3 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.