Convert inches to kilometres
1 in = 0.0000254 km
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How many kilometres are in a inch?
One inch is 0.0000254 kilometres. To convert any amount, multiply by 0.0000254. Going the other way, one kilometre is 39370.0787 inches.
What is the formula to convert in to km?
Multiply the inch figure by 0.0000254. So km = in × 0.0000254. For a quick mental estimate, dividing by about 39370.08 gets you close enough for most everyday purposes.
What does a inch actually look like?
One inch is roughly the width of an adult thumb. The inch has been exactly 25.4 millimetres since 1959. Screen sizes, pipe diameters and tyre rims are still specified in inches almost universally.
And what is a kilometre?
One kilometre is about a 12-minute walk. The kilometre is the standard road-distance unit everywhere except the United States, the United Kingdom and a handful of small territories.
Is this conversion exact?
Yes. Since the 1959 international yard and pound agreement, the imperial and metric systems are related by exact definitions rather than measurements — the inch is exactly 25.4 mm and the pound exactly 0.45359237 kg. Everything derived from those, including this conversion, is therefore exact. Round at the end rather than partway through, since rounding in before converting introduces an error the conversion then multiplies.
About in to km
How to convert inches to kilometres
Multiply by 0.0000254. One inch is 0.0000254 kilometres, and one kilometre is 39370.0787 inches.
km = in × 0.0000254
Worked example
10 in = 0.000254 km. For a sense of scale, one inch is roughly the width of an adult thumb, and one kilometre is about a 12-minute walk.
About the inch
The inch has been exactly 25.4 millimetres since 1959. Screen sizes, pipe diameters and tyre rims are still specified in inches almost universally.
About the kilometre
The kilometre is the standard road-distance unit everywhere except the United States, the United Kingdom and a handful of small territories.
Quick reference
| inches | kilometres |
|---|---|
| 1 in | 0.0000254 km |
| 2 in | 0.0000508 km |
| 5 in | 0.000127 km |
| 10 in | 0.000254 km |
| 25 in | 0.000635 km |
| 50 in | 0.00127 km |
| 100 in | 0.00254 km |
| 1000 in | 0.0254 km |
Getting it right
This conversion is exact by definition, so the only limit on accuracy is how many digits you keep. Round at the end rather than partway through — rounding in to a whole number before converting introduces an error that the conversion then multiplies.
Other length conversions
Convert kilometres back to inches, or pick any other pair with the full unit converter. Related: in to m, in to cm, in to mm.