Unit converter
Type what you want to convert, or pick the units below. The answer updates as you type.
What you enter stays on this page and is not sent anywhere.
- 1 in =
- 2.54 cm
| 25.4 mm | |
| 2.54 cm | |
| 0.0254 m | |
| 0.0000254 km | |
| 1 in | |
| 0.0833333 ft | |
| 0.0277778 yd | |
| 0.0000157828 mi | |
| 0.0000137149 NM |
Source, checked October 19, 2026: NIST Handbook 44 (2026), Appendix C: General Tables of Units of Measurement, UK Weights & Measures Act 1985, Schedule 1, NIST Guide to SI (SP 811), Appendix B.9: conversion factors by kind of quantity
How to use it
- Type a conversion such as 5 ft 9 in to cm, or tap one of the common pairs.
- Change the number or either unit; the swap button flips the direction.
- Read the answer, or tap any line in the table to switch the target unit.
Questions
How many centimeters are in an inch?
Exactly 2.54. Since 1959 the inch has been defined as 25.4 mm, the foot as 0.3048 m and the pound as 0.45359237 kg, so these conversions have no rounding of their own.
Why do US and UK gallons give different answers?
A US gallon is 231 cubic inches, about 3.785 liters. A UK imperial gallon is 4.54609 liters, about 20% larger. Pints, quarts and fluid ounces differ the same way, so the converter lists both.
How does the converter turn mpg into L/100 km?
Liters per 100 km runs the other way from mpg: a bigger number means more fuel. The converter goes through km per liter and divides, so 30 mpg (US) becomes about 7.84 L/100 km.
Is a kilobyte 1,000 or 1,024 bytes here?
This converter uses 1,024 bytes per kilobyte, the way most computers report file sizes. Drive makers often count 1,000, which is why a new drive looks smaller than its label.
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