Inches to Centimeters Converter

To convert inches to centimeters, multiply by 2.54; to convert centimeters to inches, divide by 2.54. One inch is exactly 2.54 cm, so 4 inches is 10.16 cm, 5 inches is 12.7 cm and 15 cm is 5.906 inches. The converter above works both ways, accepts fractions such as 3/4 or 1 3/8, rounds the result to the nearest 1/16 inch for a tape measure, and shows a ruler view. For 100 cm and up it also gives the length as a height in feet and inches.

This page is for anyone moving between a metric and an imperial ruler: sewing patterns and fabric, phone and TV screen sizes, picture frames, kids' height charts, shoe insoles, school homework and product dimensions on international shopping sites. Below the converter there are short exact answers for the most searched values, a 1–100 inches to cm chart, a 1–100 cm to inches chart, a fractions chart in sixteenths and a cm to feet height chart.

How to convert inches to cm (and cm to inches)

1. Write the inch length as a decimal. A fraction such as 1 3/8 becomes 1 + 3 ÷ 8 = 1.375.
2. Multiply by 2.54: 1.375 × 2.54 = 3.4925 cm.
3. For the reverse, divide centimeters by 2.54: 90 cm ÷ 2.54 = 35.4331 in.
4. For a tape measure, turn the decimal part into sixteenths: 0.433 × 16 = 6.9, so round to 7/16. 90 cm is about 35 7/16″.
5. Round only at the end. If you round 2.54 to 2.5 first, 90 cm comes out as 36 in instead of 35.43 in.

The formula is cm = in × 2.54 and in = cm ÷ 2.54. NIST Handbook 44, Appendix C, lists 1 inch as 2.54 centimeters (exactly), and NIST SP 811 prints the inch-to-centimeter factor 2.54 in bold, which marks it as exact. The value goes back to the 1959 agreement on the international yard (0.9144 m), recorded in a Federal Register notice from the National Bureau of Standards. Because the factor is exact, different converters can only disagree in how they round.

1 inch to cm

1 inch = 2.54 cm exactly, or 25.4 mm. If you are asking "1 inch for cm", the answer never needs rounding: 2 cm plus 5.4 mm. Note the symbol: 1″ (double prime) is an inch, but 1′ (single prime, often typed as 1') is a foot, which is 30.48 cm. If someone writes "1' in cm", they probably mean the foot.

15 cm to inches

15 cm = 5.9055 inches, which is 5 7/8″ to the nearest sixteenth (the fraction is 0.078 cm short). 15.5 cm is 6.1024 in, about 6 1/8″. A 15 cm ruler is just under 6 inches; 6 inches would be 15.24 cm.

90 cm to inches

90 cm = 35.4331 inches, or 2 ft 11 1/2 in (35 7/16″). That is short of a yard (36 in = 91.44 cm) by 1.44 cm. En español: 90 centímetros a pulgadas = 90 ÷ 2,54 = 35,43 pulgadas.

9 cm to inches

9 cm = 3.5433 inches, about 3 9/16″ on a ruler. 9.5 cm is 3.7402 in and 10 cm is 3.937 in.

185 cm in feet and inches

185 cm = 72.83 inches = 6 ft 1 in to the nearest inch (6 ft 0 3/4 in to the nearest quarter). In decimal feet that is 6.07 ft. Heights are usually rounded to the whole inch, which is how the height chart below is printed. For more height conversions, see the meters to feet converter, which has a full chart from 1.40 to 2.10 m.

Reading the answer on a ruler

Inch rulers and tape measures are marked in halves, quarters, eighths and sixteenths. A sixteenth of an inch is 0.15875 cm, or about 1.6 mm, so the worst rounding error to the nearest 1/16 is half that, under 0.08 cm. The converter shows the fraction and how far it is from your exact value. For sewing and woodworking that is plenty; for machined parts, keep the decimal and see the mm to inches converter, which also rounds to 1/32 and 1/64.

Centimeter rulers are simpler: each centimeter has ten millimeter marks. To read 1 3/8 in on a metric ruler, find 3.49 cm, which is 3 cm plus about 5 mm.

Worked examples

• Picture frame, 8 × 10 in: 20.32 × 25.4 cm.
• Waist 32 in: 81.28 cm. A waist of 80 cm is 31.5 in.
• Fabric, 45 in wide: 114.3 cm. Fabric 150 cm wide is 59.06 in.
• Child's height, 110 cm: 43.31 in, or 3 ft 7 in.
• Screen diagonal, 27 in: 68.58 cm.

Common mistakes

• Multiplying when you should divide. Inches to cm: multiply (the number gets bigger). Cm to inches: divide (the number gets smaller). If 10 cm turned into 25.4, you went the wrong way.
• Using 2.5 instead of 2.54. The shortcut is 1.6% off. Over 100 cm it gives 40 in instead of 39.37 in, enough to make curtains or a shelf the wrong size.
• Reading 1′ as 1 inch. The single mark is feet. 5′ 3″ is five feet three inches, 160.02 cm, not 5.3 inches.
• Writing 5.3 ft for 5 ft 3 in. 5.3 feet is 5 ft 3.6 in. See feet to inches for why decimal feet and feet-and-inches differ.
• Mixing cm and mm. 1 cm = 10 mm. A 3.5 mm part is 0.35 cm, not 3.5 cm.

Inches to cm chart: 1 to 100 inches

Every value is exact; there is no rounding because 2.54 has only two decimals.

Cm to inches chart: 1 to 100 cm

Decimal inches to four places and the nearest 1/16 inch mark.

Half-centimeter values in inches

Inch fractions to cm (every 1/16 inch)

Add 2.54 cm for each whole inch. For example 1 3/8 in = 2.54 + 0.9525 = 3.4925 cm.

Cm to feet and inches height chart (140–215 cm)

Heights rounded to the nearest inch, the way most forms ask for height.

Related converters: mm to inches for small parts, feet to inches, meters to feet for heights and room sizes, and decimal feet to feet and inches for plans and survey numbers.

Frequently asked questions

Sources & method

• NIST Handbook 44 (2026), Appendix C — 1 inch = 2.54 centimeters (exactly); 1 foot = 12 inches (exactly)
• NIST SP 811, Appendix B.8 — inch to centimeter factor 2.54 E+00 (bold = exact)
• Federal Register Notice 59-5442 (June 30, 1959) — Refinement of values for the yard and the pound

Results are estimates for general information. Found an error? It helps everyone — see our methodology.