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Distance converter
Pick the unit you have and the unit you want. Everything converts through meters using the exact international definitions — 1 mi = 1,609.344 m, 1 nmi = 1,852 m.
CONVERTER · EVERYDAY · DISTANCE
Kilometers to Miles
1 kilometer = 0.621371 miles — exactly, because the international mile is defined as 1,609.344 meters. So 5 km = 3.10686 miles, a 10K is 6.21371 miles, a half marathon is 13.10938, and a marathon is 26.21876. Convert either direction below, across kilometers, meters, miles, feet, yards, and nautical miles.
The 60-second rule
Miles = kilometers × 0.621371. Kilometers = miles × 1.609344. The factor is exact, not approximate: the international mile is defined as 1,609.344 meters, so 1,000 ÷ 1,609.344 = 0.621371 miles per kilometer, forever. At the defaults: 5 km × 0.621371 = 3.10686 miles — that is why a 5K is universally called 3.1 miles. Going the other way, 1 mile × 1.609344 = 1.60934 km.
The worked example, line by line
Setup: convert 5 kilometers to miles — “how many miles is a 5K”.
The factor. 1 mile = 1,609.344 m exactly, so 1 km = 1,000 ÷ 1,609.344 = 0.621371 mi. This is a defined constant, not a measurement — it never changes.
The multiply. 5 × 0.621371 = 3.10686 miles. Runners round it to 3.1, which is the number on every training plan.
The reverse check. 3.10686 × 1.609344 = 5.00000 km — the round trip lands exactly where it started.
Branch — 10K: 10 × 0.621371 = 6.21371 miles, the standard 6.2-mile shorthand.
Branch — half marathon (21.0975 km): 21.0975 × 0.621371 = 13.10938 miles, the 13.1 on every race bib.
Branch — marathon (42.195 km): 42.195 × 0.621371 = 26.21876 miles, the famous 26.2.
Branch — nautical miles: 5 km = 2.69978 nautical miles (1 nmi = 1,852 m exactly) — the unit for sailors and pilots, noticeably shorter than statute miles.
Runner’s quick-reference table
| Distance | Kilometers | Miles |
|---|---|---|
| Kilometer | 1 | 0.62137 |
| 5K | 5 | 3.10686 |
| 10K | 10 | 6.21371 |
| Half marathon | 21.0975 | 13.10938 |
| Marathon | 42.195 | 26.21876 |
Output · formula · meaning
| Output | Formula | What it means |
|---|---|---|
| Converted distance | value × (from-unit in meters) ÷ (to-unit in meters) | 3.10686 miles at the defaults — your distance in the target unit. |
| Conversion rate | 1 from-unit = (from-meters ÷ to-meters) to-units | 1 kilometer = 0.621371 miles at the defaults — the rate the page multiplied by. |
| Runner check | pace ÷ 0.621371 | 5:00/km = 8:02.8/mi — per-mile pace is always a bigger number than per-kilometer pace. |
Who uses this
- The first-time 5K runner: signed up for a race measured in “K”, sees 5 km = 3.10686 miles, and finally understands the training plan’s “3.1 miles”.
- The pace translator: training at 5:00 per kilometer needs the per-mile equivalent — 8:02.8/mi — to talk pace with mile-based running partners.
- The car buyer reading a foreign spec sheet: a European listing shows 12.5 km/L or a trip odometer in km; converts distances with the exact factor before doing fuel math.
- The sailor or pilot: converts nautical miles (1,852 m) against statute miles — 5 km is 2.69978 nmi but 3.10686 statute miles, and mixing them up is a real navigation error.
Accuracy & limitations
The kilometer-to-mile factor is exact by definition: the international mile is 1,609.344 meters, so 1 km = 0.621371 mi with no measurement uncertainty. The only “error” in any conversion is display rounding — this page shows up to 5 decimal places, and 5 km displays as 3.10686 rather than the full 3.106855961…. The mile variants are separate units: statute miles (1,609.344 m), nautical miles (1,852 m), and the obsolete survey mile (1,609.347 m) — this page uses the international statute mile, and the converter’s nautical-mile option is the one for aviation and marine use. For GPS distances, remember the device measures the shortest path; a 5K course may read 5.1–5.2 km on your watch.
Cite this calculatorBright Side Kit. “Kilometers to Miles.” brightoolbox.com, 2026.
Bright Side Kit. "Kilometers to Miles." https://brightoolbox.com/kilometers-to-miles/ Accessed October 23, 2026.Frequently asked questions
How many miles is a 5K?
3.10686 miles — 5 × 0.621371. Runners call it 3.1 miles, which is the number on every training plan and race shirt. Your GPS may show 5.1–5.2 km on race day because it tracks your actual path, not the measured shortest course.
What is the exact conversion factor from km to miles?
1 km = 0.621371192 miles (the calculator uses the exact international definition: 1 mile = 1,609.344 m). For quick mental math, 0.62 is close enough — and 1.609 goes the other way, miles to kilometers.
How do I convert my running pace from km to miles?
Divide your per-kilometer pace by 0.621371 — or multiply by 1.609344. A 5:00/km pace becomes 8:02.8 per mile. Per-mile paces are always larger numbers than per-kilometer paces because a mile is longer.
How many miles is 10K?
6.21371 miles — 10 × 0.621371, universally shortened to 6.2 miles. Double the 5K’s 3.10686, exactly as it should be.
How many miles is a marathon?
26.21876 miles — 42.195 × 0.621371, the famous 26.2. The half marathon (21.0975 km) is 13.10938 miles, the 13.1 on every bib.
Is a nautical mile the same as a regular mile?
No. A nautical mile is 1,852 meters (about 1.1508 statute miles); a statute mile is 1,609.344 meters. Five kilometers is 3.10686 statute miles but only 2.69978 nautical miles — pick the right one in the converter’s unit list.
Why do some countries still use miles?
Tradition and road signs. The US, UK, and a few others kept miles for roads and some races, while World Athletics sanctions all international competition in meters. The converter handles both worlds: km for the metric side, statute miles for the imperial side.