# Inches to cm Converter URL: https://speedycalculator.com/calculators/conversion/inches-to-cm/ Last updated: 2026-10-25 > Convert inches (in) to centimetres (cm): 1 inch = 2.54 cm, so multiply by 2.54 or divide by 0.39370079. Both fields are editable, so you can also type in centimetres and get inches back. ## Inputs - Inches (in) ## Results - Centimetres ## Formula ``` 1 in = 2.54 cm 1 cm = 0.39370079 in cm = in × 2.54 ``` ## Explanation Multiply inches by 2.54 to get centimetres. Screen diagonals, wheel sizes and picture frames are often given in inches, while metric countries quote centimetres or millimetres. ### How to use the Inches to cm Converter - Type the number of inches into the **Inches** field. Decimals such as 6 are fine. - Read the answer in **Centimetres** – it updates as you type, with no button to press. - To convert the other way, type into **Centimetres** and the inches are recalculated. - Press **Copy results** to copy both values with the page title, or **Copy link** to share this exact conversion. This page converts only in ⇄ cm. Need a different unit? Use the general length converter, where you can choose any “from” and “to” unit. ### How it works Both units measure length, so they are always in the same ratio: one inch equals 2.54 centimetres. The calculator multiplies the number of inches you type by 2.54 to give centimetres, and when you type into the centimetres field it divides by the same factor to give inches. Because the ratio never changes, doubling the inches always doubles the centimetres. Results are calculated at full precision and rounded only for display (up to eight decimal places, with very large or small values shown in scientific notation). ### How to convert inches to centimetres - Write down the value in inches, for example **12 in**. - Multiply by the conversion factor 2.54 (because 1 inch = 2.54 cm). - 12 × 2.54 = **30.48 cm**. - To go back from centimetres to inches, divide by 2.54 – or multiply by 0.39370079. ### in to cm conversion table InchesCentimetresCentimetresInches0.25 in0.635 cm1 cm0.39370079 in1 in2.54 cm2 cm0.78740157 in2 in5.08 cm5 cm1.9685039 in4 in10.16 cm10 cm3.9370079 in6 in15.24 cm20 cm7.8740157 in8 in20.32 cm50 cm19.685039 in12 in30.48 cm100 cm39.370079 in18 in45.72 cm1,000 cm393.70079 in32 in81.28 cm43 in109.22 cm55 in139.7 cm75 in190.5 cm ### What is an inch? The inch has been defined as exactly 25.4 mm since 1959. It is used in the U.S. for almost everything and worldwide for screen sizes, wheel and tyre sizes, pipe threads and many tools. ### What is a centimetre? A centimetre is one hundredth of a metre (10 mm). It is the everyday metric unit for body height, clothing, furniture and school rulers. ### Quick mental conversion For a fast estimate, multiply inches by about **2.5** to get centimetres; the error is about 1.6%. Use the calculator above when you need the exact figure. ### Common mistakes to avoid Mixing the international foot (0.3048 m) with the old u.s. survey foot, confusing nautical and statute miles, and writing decimal feet such as 5.5 ft as “5 ft 5 in” (it is 5 ft 6 in). ## Worked example Inputs — Inches: 12 in. Results — **Centimetres = 30.48 cm**. ## FAQ **How many cm is 12 inches?** 30.48 cm, one foot. **How big is a 55-inch TV in cm?** 139.7 cm diagonally. **How do I convert inches to centimetres?** Multiply the number of inches by 2.54. For example, 12 in × 2.54 = 30.48 cm. **How do I convert centimetres back to inches?** Divide by 2.54 (or multiply by 0.39370079), or simply type the value into the centimetres field above. **What is 10 in in centimetres?** 10 in = 25.4 cm. **What is 5 in in centimetres?** 5 in = 12.7 cm. **Is this conversion exact?** Yes. The factor comes from the official definitions of both units (NIST and the SI), so the only difference you may see is rounding in the last displayed digit. **Can I convert to other units on this page?** This page converts only between inches and centimetres. To pick any length unit, use the general length converter linked under Related calculators. **What formula does the Inches to cm Converter use?** 1 in = 2.54 cm. ## Sources - [NIST Special Publication 811 – Guide for the Use of the International System of Units](https://www.nist.gov/pml/special-publication-811) - [NIST Handbook 44 Appendix C – General tables of units of measurement](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition)