What this converter does
This tool changes a length from inches and feet into centimeters, or from centimeters back into feet and inches. Type your measurement and the answer appears right away. Inches and feet are the everyday length units in the United States. Centimeters and meters are used almost everywhere else, and in science, medicine and most product specifications.
People need an inches to cm converter for many reasons: filling in a form that asks for height in centimeters, checking the size of furniture sold overseas, buying clothes from an international shop, or doing homework. The tool also shows millimeters and meters, so you can pick the unit your task needs.
How to use it
- Choose the direction. "Feet and inches to centimeters" is the default. Pick the second option to go from centimeters to feet and inches.
- Type the numbers. For a height such as 5 ft 9 in, enter 5 in the feet box and 9 in the inches box. If you only know inches, leave feet at 0 and type the total in the inches box, for example 36.
- Choose the number of decimal places. One decimal place is enough for most uses.
- Read the results. The main answer is shown in large type, with the other units below it.
Negative lengths are not accepted, because a length cannot be less than zero.
The conversion formula
The relation between inches and centimeters is not an approximation. Since the international agreement of 1959, one inch has been defined as exactly 2.54 centimeters. The National Institute of Standards and Technology (NIST) lists this factor in its guide to the International System of Units.
centimeters = inches × 2.54
inches = centimeters ÷ 2.54
1 foot = 12 inches = 30.48 cm
To convert feet and inches together, first change everything into inches: total inches = feet × 12 + inches. Then multiply by 2.54. For 5 ft 9 in, that is (5 × 12 + 9) = 69 inches, and 69 × 2.54 = 175.26 cm.
Going the other way
To turn centimeters into feet and inches, divide by 2.54 to get total inches. Then divide by 12. The whole number is the feet, and the remainder is the inches. For 175 cm, 175 ÷ 2.54 = 68.898 inches. That is 5 feet (60 inches) and 8.898 inches, or about 5 ft 8.9 in.
A quick mental shortcut
To estimate, multiply inches by 5 and divide by 2, which is the same as multiplying by 2.5. For 10 inches you get 25 cm. The exact answer is 25.4 cm, so the shortcut is close but a little low. Use the converter when you need a precise number.
Worked examples
| Starting value | Calculation | Result |
|---|---|---|
| 1 inch | 1 × 2.54 | 2.54 cm |
| 12 inches (1 foot) | 12 × 2.54 | 30.48 cm |
| 5 ft 9 in | 69 × 2.54 | 175.26 cm |
| 5 ft 10 in | 70 × 2.54 | 177.8 cm |
| 6 ft 2 in | 74 × 2.54 | 187.96 cm |
| 160 cm | 160 ÷ 2.54 = 62.99 in | about 5 ft 3 in |
| 170 cm | 170 ÷ 2.54 = 66.93 in | about 5 ft 6.9 in |
| 180 cm | 180 ÷ 2.54 = 70.87 in | about 5 ft 10.9 in |
| 100 cm (1 meter) | 100 ÷ 2.54 = 39.37 in | 3 ft 3.4 in |
Notice that 180 cm is just under 6 feet. Six feet is exactly 182.88 cm.
Where these units are used
The United States still uses inches and feet for height, room sizes, screen sizes and many building materials. The United Kingdom uses a mix: people often give height in feet and inches, while shops and schools use centimeters. Most other countries use only the metric system. That is why a passport form, a medical chart or an online store in another country may ask for centimeters while you think in feet and inches.
Screen sizes and tire widths are often quoted in inches even in metric countries, while the same product's packaging lists centimeters or millimeters. Being able to move between the two systems saves mistakes when you order parts, frames or furniture.
Rounding tips
For height, whole centimeters are plenty. For sewing, woodworking or print sizes, one or two decimal places are more useful. The converter rounds only at the very end, so rounding errors do not build up. Remember that a tape measure is rarely accurate to better than a millimeter, so extra decimals do not make a measurement more reliable.
Frequently asked questions
- How many centimeters are in an inch?
- Exactly 2.54 centimeters. This is a definition, not a rounded measurement.
- How do I convert inches to cm by hand?
- Multiply the number of inches by 2.54. For example, 20 inches × 2.54 = 50.8 cm.
- How do I convert feet and inches to cm?
- Multiply the feet by 12 and add the inches. Then multiply the total by 2.54. For 6 ft 0 in, 72 × 2.54 = 182.88 cm.
- What is 175 cm in feet and inches?
- About 5 feet 8.9 inches, or 5 ft 9 in when rounded to the nearest inch.
- Is the conversion exact?
- Yes. The factor of 2.54 is exact, so only the displayed result is rounded, to the number of decimal places you choose.
Things to keep in mind
This converter changes units only. It does not tell you whether a size will fit, whether clothing runs large or small, or whether a medical measurement is healthy. For clothing and shoes, size charts differ between brands and countries, so check the seller's own chart. For medical or legal forms, follow the instructions given by the organization that asks for the number. Also, a person's height can differ by about a centimeter between morning and evening, so small differences in a result are normal.