inch (in)
1 inch = 0.0254 metres
What is inch?
An inch is a unit of length in imperial and US customary systems equal to 1/12 of a foot. It is widely used for screen sizes, display resolutions, pipe diameters, and small-scale measurements in everyday contexts.
Notes: Imperial/USCS unit
Real-world uses
Inches are used throughout the United States, Canada (partially), and the UK for screen sizes, pipe diameters, lumber dimensions, and screw/bolt specifications. Display sizes for monitors, TVs, and phones are universally quoted in diagonal inches.
History
The inch has ancient origins, traditionally defined as the width of a man's thumb or three barleycorns laid end to end. It was standardized internationally in 1959 as exactly 25.4 mm, reconciling slight differences between British and American definitions.
Common mistakes
Assuming inch fractions are decimal—1/8 inch is 0.125 inches, not 0.18. Also, confusing nominal lumber sizes (a "2x4" is actually 1.5 × 3.5 inches) with actual inch measurements.
When is this conversion used?
Converting between inch and metre is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. This conversion is frequently needed in construction, architecture, and real estate where building codes may specify dimensions in one system while materials are sold in another. Screen sizes, paper dimensions, and clothing measurements often require converting between centimetres and inches, especially when shopping internationally.
How to convert inch to metre
To convert inch to metre, multiply the value by 0.0254.
Conversion formula (from base unit)
x * 0.0254
Measurement standards
The metre is one of seven SI base units, maintained by the International Bureau of Weights and Measures (BIPM). Since 2019, it is defined by fixing the numerical value of the speed of light in vacuum to exactly 299,792,458 metres per second.
Did you know?
A human hair is roughly 70 micrometres wide, while a single gold atom measures about 0.144 nanometres in diameter — meaning you could line up nearly half a million atoms across the width of one hair.
| inches | metres |
|---|---|
| 0.1 | 0.00254 |
| 0.5 | 0.0127 |
| 1 | 0.0254 |
| 2 | 0.0508 |
| 5 | 0.127 |
| 10 | 0.254 |
| 25 | 0.635 |
| 50 | 1.27 |
| 100 | 2.54 |
| 250 | 6.35 |
| 500 | 12.7 |
| 1,000 | 25.4 |
Common values
| inches | metres | |
|---|---|---|
| Height of a door | 82.67716535 inches | 2.1 metres |
| Basketball court length | 1,102.36220472 inches | 28 metres |
| Football field (soccer) | 4,133.85826772 inches | 105 metres |
| Marathon distance | 1,661,220.47244094 inches | 42,195 metres |
| Altitude of a cruising airplane | 420,000 inches | 10,668 metres |
Full inch conversion table
| Unit | Value | Factor |
|---|---|---|
| metre | 1 in = 0.0254 m | × 0.0254 |
| kilometre | 1 in = 0.0000254 km | × 0.0000254 |
| centimetre | 1 in = 2.54 cm | × 2.54 |
| millimetre | 1 in = 25.4 mm | × 25.4 |
| foot | 1 in = 0.08333333 ft | × 0.08333333 |
| mile | 1 in = 0.00001578 mi | × 0.00001578 |
| yard | 1 in = 0.02777778 yd | × 0.02777778 |
| micrometre | 1 in = 25,400 µm | × 25,400 |
| nanometre | 1 in = 25,400,000 nm | × 25,400,000 |