# Inch Converter URL: https://speedycalculator.com/calculators/conversion/inch-converter/ Last updated: 2026-10-25 > The inch converter converts length between centimetres, millimetres, metres, feet, yards, mils and more. Choose any “from” and “to” unit, type a number into any field and every other unit updates instantly; all conversion factors are exact definitions. ## Inputs - From (in, m, km, cm, mm, dm, µm, nm, Å, ft, yd, mi, nmi, mil, furlong, chain, rod, fathom, hand, league, AU, ly, pc, R☉, px (96 dpi), pt, gaj) ## Results - To - Millimetres - Metres - Feet - Yards - Mils ## Formula ``` 1 in = 2.54 cm 1 in = 25.4 mm 1 in = 0.0254 m 1 in = 0.083333333 ft 1 in = 0.027777778 yd ``` ## Explanation An inch is exactly 25.4 mm. Screens, tyres, pipes, bolts and paper are often specified in inches even in metric countries, so it pays to convert precisely. ### How to use the Inch Converter - Pick the unit you are starting from in the **From** menu and type your value. - Pick the unit you want in the **To** menu. The heading changes to match – for example “Inches to Centimeters Converter”. - The most common length units are shown below at the same time, so you can compare them at a glance. - Type into any result to convert backwards, then use **Copy results** – the copied text starts with the heading for your chosen units. Results update as you type. Everything is calculated in your browser. ### How it works Every length unit is defined by an exact factor relative to the metre (the base unit). The calculator first turns the value you type into metres, then turns that into the unit you picked in the “To” menu and into each of the common units below it. This two-step method means any unit can be converted to any other – 27 units are available in each menu – and you can type into any field, including a result, to work in the other direction. Changing a unit menu keeps the quantity the same and just re-expresses it, and the page heading and copied results follow your choice. ### How to convert length units - Choose the unit you have in the **From** menu and type the value, for example **1 in**. - Choose the unit you want in the **To** menu, for example centimetres. The page heading changes to “Inches to Centimeters Converter”. - The calculator multiplies by the metre factor of the “from” unit and divides by the factor of the “to” unit: 1 in × 0.0254 ÷ 0.01 = **2.54 cm**. ### 1 inch in common units UnitValueCentimetres (cm)2.54Millimetres (mm)25.4Metres (m)0.0254Feet (ft)0.083333333Yards (yd)0.027777778Mils (mil)1000 ### Inches conversion table Inchescmmmmft0.250.6356.350.006350.0208333330.51.2712.70.01270.04166666712.5425.40.02540.08333333325.0850.80.05080.16666667615.24152.40.15240.51230.48304.80.304812460.96609.60.609623691.44914.40.91443 ### 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. ### What is a millimetre? A millimetre is one thousandth of a metre. Engineering drawings, construction plans, rainfall, screws, bolts and jewellery are all dimensioned in millimetres. ### 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 — From: 1 in. Results — **To = 2.54 cm**; Millimetres = 25.4 mm; Metres = 0.0254 m; Feet = 0.08333333 ft; Yards = 0.02777778 yd; Mils = 1,000 mil. ## FAQ **How many cm in an inch?** Exactly 2.54 cm. **How many inches in a yard?** 36. **What is a mil?** One thousandth of an inch (0.0254 mm), used for film and sheet thickness. **How do I change the units?** Pick any unit in the From and To menus. The value is converted in place, and the heading changes to show your conversion, for example “Inches to Centimeters Converter”. **Can I type into any field?** Yes. Every field is editable, so you can start from whichever unit you have. **How many units can I convert between?** 27 length units, from the everyday to the specialised. **Which units are exact?** All factors here are exact by definition except astronomical and similar reference values, which use internationally agreed constants. **What formula does the Inch 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)