Miles to Kilometers (mi to km) Converter
A bidirectional converter for distance (mi ↔ km) and speed (mph ↔ kph). Enter a value in any field to convert instantly.
Distance Conversion (mi ↔ km)
Speed Conversion (mph ↔ kph)
For converting speeds, such as road signs or cycling data.
How to Convert Miles to Kilometers
Whether you're converting distance (miles) or speed (mph), the conversion factor is the same. There are two main ways to do it: the exact formula for precision, and a simple mental math trick for quick estimates.
The Exact Formula
The internationally accepted conversion factor is:
To convert from miles to kilometers, you simply multiply the mile value by 1.609344.
Example: Convert 100 miles to km.
100 mi × 1.609344 = 160.9344 km
The Easy Mental Math Trick (The "5 and 8" Rule)
For a fast, on-the-go estimate (like seeing a road sign in the US), this trick is extremely accurate. It's popular with European drivers and cyclists.
Example: Convert 50 mph to kph in your head.
- Divide by 5:
50 / 5 = 10 - Multiply by 8:
10 × 8 = 80 kph
(The exact answer is 80.47 kph, so this "Fibonacci" trick is incredibly close!)
Common Conversion Charts
Distance (mi to km)
| Miles (mi) | Kilometers (km) |
|---|---|
| 1 mi | 1.61 km |
| 5 mi | 8.05 km |
| 10 mi | 16.09 km |
| 25 mi | 40.23 km |
| 50 mi | 80.47 km |
| 100 mi | 160.93 km |
Speed (mph to kph)
| Miles per Hour (mph) | Kilometers per Hour (kph) |
|---|---|
| 25 mph | 40.2 kph |
| 30 mph | 48.3 kph |
| 50 mph | 80.5 kph |
| 60 mph | 96.6 kph |
| 70 mph | 112.7 kph |
Frequently Asked Questions (FAQ)
What is the formula for miles to km?
The formula is: Kilometers = Miles × 1.609344.
How many km in a mile?
There are **1.609344 kilometers** in 1 mile.
What is the easy trick to convert miles to km in your head?
A very popular and accurate mental math trick is the '5 and 8' rule: **Divide the miles by 5, then multiply by 8.** For 50 miles: 50 / 5 = 10. 10 * 8 = 80 km. (The exact answer is 80.47 km).