Inch to Kilometer (in to km)
Result
0.0000254 Kilometer
Formula
km = in × 0.0000254
1 in = 0.0000254 km, and 1 km = 39,370.07874 in.
The metre is the SI base unit, defined by the speed of light. Since the 1959 international yard and pound agreement the imperial and US customary units are defined exactly in metres: 1 yard = 0.9144 m, so 1 foot = 0.3048 m, 1 inch = 2.54 cm and 1 mile = 1,609.344 m.
Worked examples
- 1 in × 0.0000254 = 0.0000254 km
- 10 in × 0.0000254 = 0.000254 km
- 100 in × 0.0000254 = 0.00254 km
Common mistakes
- Decimal feet are not feet-and-inches: 5.75 ft is 5 ft 9 in, not 5 ft 7.5 in. Split off the whole feet and multiply the remainder by 12.
- A nautical mile (1,852 m) is about 15% longer than a statute mile (1,609.344 m). Knots and sea charts use nautical miles.
- The US survey foot (1200/3937 m) differs from the international foot by 2 parts per million. It was retired from official US use at the end of 2022 but still appears in older land records.
Inch to Kilometer table
| Inch (in) | Kilometer (km) |
|---|---|
| 1 | 0.0000254 |
| 2 | 0.0000508 |
| 5 | 0.000127 |
| 10 | 0.000254 |
| 20 | 0.000508 |
| 50 | 0.00127 |
| 100 | 0.00254 |
| 1,000 | 0.0254 |
The units
- Inch (in)
- Exactly 2.54 cm by the 1959 international agreement; 12 inches make a foot.
- Kilometer (km)
- 1,000 metres. Road distances and speed limits in most of the world use kilometres.
Sources for these factors
- The International System of Units (SI Brochure), 9th edition — BIPM
- Handbook 44 (2024), Appendix C: General Tables of Units of Measurement — NIST
- Guide for the Use of the International System of Units (SP 811), Appendix B: conversion factors — NIST
Last reviewed against these sources. An automated check recomputes every factor from its definition on each build. How we check accuracy