Miles to Kilometers Converter (+ km to miles)
Convert miles to kilometers instantly. 1 mile = 1.609344 km exactly (NIST). Works both ways. Includes reference table for common running, driving, and cycling distances.
- Data verified · June 2026
- Edited by Martín Rodríguez
- Formula verified by automated tests
- Private — runs on your device
See step-by-step calculation
See this calculation step by step
See period-by-period detail
How to use this calculator
Follow this tool’s steps, then review its formula, assumptions, and limits below.
When to use this calculator
- Converting a US road-trip distance (e.g., 250 miles from NYC to Washington D.C.) into kilometers for a European friend's navigation app that only accepts metric input.
- Translating a 10K race distance (10 km) into miles (6.214 mi) to set the correct treadmill distance at a US gym.
- Checking whether a hiking trail listed as 14.5 km in a Canadian park map exceeds the 8-mile daily limit recommended by your tour operator.
- Calculating the round-trip fuel cost for a 45-mile commute (90 miles total = 144.84 km round trip).
- Converting speed-limit signs when driving a rental car in the UK (e.g., 70 mph motorway limit → 112.65 km/h).
- Preparing for a marathon: confirming that 26.219 miles equals exactly 42.195 km, the IAAF-certified distance.
Speed limit conversion: mph ↔ km/h
The same 1.609344 factor converts speed — useful when driving a rental abroad.
| mph | km/h | km/h | mph |
|---|---|---|---|
| 20 | 32.2 | 30 | 18.6 |
| 30 | 48.3 | 50 | 31.1 |
| 40 | 64.4 | 60 | 37.3 |
| 50 | 80.5 | 80 | 49.7 |
| 60 | 96.6 | 100 | 62.1 |
| 70 | 112.7 | 120 | 74.6 |
| 80 | 128.7 | 130 | 80.8 |
km/h = mph × 1.609344; mph = km/h × 0.621371. The hour cancels, so the distance factor applies directly to speed. 70 mph (US/UK motorway) = 112.7 km/h; 120 km/h (EU motorway) = 74.6 mph.
Race and running distances: miles ↔ km
Exact equivalents for the most-searched running and cycling distances.
| Distance | Miles | Kilometers |
|---|---|---|
| 1 mile | 1.000 | 1.609 |
| 5K | 3.107 | 5.000 |
| 10K | 6.214 | 10.000 |
| 10 miles | 10.000 | 16.093 |
| Half marathon | 13.109 | 21.098 |
| Marathon | 26.219 | 42.195 |
| 50K ultra | 31.069 | 50.000 |
| 100 miles | 100.000 | 160.934 |
km = mi × 1.609344. The marathon distance (42.195 km) is World Athletics-certified; the half is exactly half of it (21.0975 km, shown rounded).
How it works
How the Conversion Works
The factor 1.609344 is an exact, legally-defined constant (not a rounded approximation). It derives from:
> 1 mile = 1,760 yards; 1 yard = 0.9144 m (exact) → 1,760 × 0.9144 = 1,609.344 m = 1.609344 km
Miles → Kilometers: km = mi × 1.609344
Kilometers → Miles: mi = km ÷ 1.609344 (= km × 0.621371)---
Miles to Kilometers Reference Table
| Miles (mi) | Kilometers (km) | Common context |
|---|---|---|
| 0.5 | 0.805 | Short walk / half-mile track |
| 1 | 1.609 | 1-mile run benchmark |
| 3.107 | 5.000 | 5K race |
| 5 | 8.047 | Common morning run |
| 6.214 | 10.000 | 10K race |
| 10 | 16.093 | Long training run |
| 13.109 | 21.098 | Half marathon |
| 26.219 | 42.195 | Full marathon (IAAF) |
| 50 | 80.467 | Short road trip |
| 100 | 160.934 | Century bike ride / day trip |
| 500 | 804.672 | Cross-state drive |
---
Kilometers to Miles Reference Table
| Kilometers (km) | Miles (mi) | Common context |
|---|---|---|
| 1 | 0.621 | 1K run |
| 5 | 3.107 | 5K race |
| 10 | 6.214 | 10K race |
| 21.098 | 13.109 | Half marathon |
| 42.195 | 26.219 | Full marathon |
| 100 | 62.137 | Century road ride |
| 400 | 248.548 | Common city-to-city drive |
---
Worked Examples
Example 1 — Road trip planning (mi → km)
A driver plans a 350-mile trip and needs the distance in km for a metric GPS:
> 350 mi × 1.609344 = 563.27 km
Example 2 — Trail running (km → mi)
A race is advertised as 32 km. An American runner wants the mileage:
> 32 km ÷ 1.609344 = 19.884 mi
Example 3 — Speed conversion (mph → km/h)
Since speed is distance per hour, the same factor applies:
> 75 mph × 1.609344 = 120.70 km/h
---
Common Mistakes
1. Using 1.6 instead of 1.609344 — The 1.6 shortcut introduces a 0.58% error; over 100 miles this is nearly 1 km off.
2. Confusing statute miles with nautical miles — 1 nautical mile = 1.852 km, not 1.609344 km. Never apply the road-mile factor to aviation/maritime distances.
3. Inverting the direction — When converting km → mi, divide by 1.609344 (do NOT multiply).
Example: 10 miles to kilometers
Frequently asked questions
How many kilometers is 1 mile?
How many miles is 1 kilometer?
How do I quickly convert miles to km in my head?
How far is a 5K in miles?
Does mph to km/h use the same conversion factor?
What is the difference between a statute mile and a nautical mile?
Why does the US still use miles instead of kilometers?
How accurate is this miles-to-km calculator?
Sources & references
Methodology & trust
Math calculator with its formula verified automatically against NIST – Appendix B: Conversion Factors (mile, international), per our editorial policy and methodology.
Updated: June 12, 2026. Parameters are verified periodically against the cited sources.
Calculations run 100% in your browser. We do not store or transmit your data.
Indicative results. For critical decisions, consult a professional.
📌 How to cite this calculator
Rodríguez, M. (2026). Miles to Kilometers Converter (+ km to miles). Hacé Cuentas. https://hacecuentas.com/en/conversion-miles-kilometers
@misc{hacecuentas_conversion_miles_kilometers_2026,
author = {Rodríguez, Martín},
title = {{Miles to Kilometers Converter (+ km to miles)}},
year = {2026},
howpublished = {\url{https://hacecuentas.com/en/conversion-miles-kilometers}},
note = {Hacé Cuentas}
} Content licensed under CC-BY 4.0 — reuse it citing the source with a link to Hacé Cuentas.