KMtoMiles – Free Kilometers to Miles Converter
Convert km to mi and miles to km instantly as you type. 100% free, secure and client-side.
Quick Answer: How Many Miles in a Kilometer?
1 kilometer = 0.621371 miles and 1 mile = 1.609344 kilometers. To convert km to mi, multiply kilometers by 0.621371. Example: 10 km × 0.621371 = 6.21371 mi. KMtoMiles does this instantly and securely in your browser — nothing is uploaded.
Why Use KMtoMiles?
Instant Two-Way Conversion
Type in either box — km to miles or miles to km updates on every keystroke.
One-Click Unit Swap
Flip the direction instantly to convert miles to kilometers.
Adjustable Precision
Round results from 0 to 5 decimal places for running, driving or science.
Private & Offline-Ready
Pure vanilla JavaScript. Nothing is uploaded, no sign-up, no tracking of your inputs.
Kilometer to Mile Formula (Step by Step)
One kilometer equals 0.621371 miles, and one international mile equals exactly 1.609344 kilometers.
How to convert km to miles
- Take your distance in kilometers, e.g.
10 km. - Multiply it by the conversion factor:
10 × 0.621371. - The result is
6.21371 miles— round as needed (≈6.21 mi).
Quick mental math
- Multiply km by 0.6 for a rough estimate (10 km ≈ 6 mi).
- Or use the Fibonacci trick: 5 km ≈ 3 mi, 8 km ≈ 5 mi, 13 km ≈ 8 mi.
Your value: 1 km × 0.621371 = 0.621371 mi
Common Distances: km to Miles
🏃 Running Races
5K = 3.107 mi · 10K = 6.214 mi · Half marathon (21.0975 km) = 13.109 mi · Marathon (42.195 km) = 26.219 mi
🚗 Speed Limits
50 km/h = 31.07 mph · 80 km/h = 49.71 mph · 100 km/h = 62.14 mph · 120 km/h = 74.56 mph
✈️ Longer Trips
200 km = 124.27 mi · 500 km = 310.69 mi · 1,000 km = 621.37 mi
Km to Miles Conversion Table (1–100 km)
| Kilometers (km) | Miles (mi) | Kilometers (km) | Miles (mi) |
|---|
Frequently Asked Questions
How many miles are in 1 km?
1 kilometer equals 0.621371 miles. Conversely, 1 mile equals 1.609344 kilometers.
What is the formula to convert km to miles?
Multiply kilometers by 0.621371: miles = km × 0.621371. For example, 10 km × 0.621371 = 6.21371 miles.
How do I convert miles to km?
Multiply miles by 1.609344 (or divide by 0.621371): km = miles × 1.609344. For example, 5 miles = 8.04672 km. Use the ↔ swap button above to do it instantly.
How many miles is a 5K run?
A 5K is about 3.11 miles. A 10K is about 6.21 miles, a half marathon is 13.1 miles and a marathon is 26.2 miles.
Is KMtoMiles free and private?
Yes. KMtoMiles is 100% free and runs entirely in your browser with vanilla JavaScript. No data is sent to any server and no sign-up is required.
Is a kilometer longer than a mile?
No. A mile is longer. One mile is about 1.61 kilometers, so a kilometer is roughly 62% of a mile.