Why Convert Kilometers to Miles?
Converting between kilometers (km) and miles (mi) is one of the most common length conversions. Whether for engineering, cooking, travel, or science, knowing how to quickly convert km to mi saves time and prevents errors.
Length conversions between km and mi are essential in international travel, construction, and sports. Airline carry-on luggage limits are typically defined in centimeters (55×40×20 cm), but US travelers think in inches. Architects and contractors regularly convert between metric and imperial measurements when working on international projects. In athletics, track distances may be in meters while road races use miles or kilometers.
How to Convert Kilometers to Miles
To convert kilometers to miles, use the following formula:
mi = km × 0.6213711922
Example: 1 km = 0.6213711922 mi
For example, 5 km = 3.106855961 mi, 10 km = 6.213711922 mi, and 100 km = 62.13711922 mi. Our calculator above performs this conversion instantly with full precision — no rounding errors.
Common Use Cases
- 5K run distance: 5 km = 3.106855961 mi
- 10K run distance: 10 km = 6.213711922 mi
- Full marathon distance: 42.195 km = 26.21875746 mi
- Half marathon distance: 21.1 km = 13.11093216 mi
- Typical intercity driving distance: 100 km = 62.13711922 mi
Common Mistakes to Avoid
- Confusing similar units: Don't mix up meters (m) with miles (mi) — they differ by a factor of ~1600. Always check the unit symbol.
- Rounding too early: When converting km to mi, carry at least 4 decimal places in intermediate calculations to avoid compounding errors.
- Forgetting unit labels: Always write the unit symbol after the number. "5.5" is ambiguous — "5.5 mi" is clear.
Pro Tips
- Memorize the factor: 1 km = 0.6213711922 mi. For quick mental math, remember this base conversion.
- Quick reference: 5 km = 3.106855961 mi · 10 km = 6.213711922 mi · 25 km = 15.53427981 mi · 50 km = 31.06855961 mi · 100 km = 62.13711922 mi
- Bookmark this page: Save this converter for instant access. It works offline once loaded — no internet needed.
Kilometers to Miles Conversion Table
| km | mi |
|---|---|
| 0.01 km | 0.006213711922 mi |
| 0.1 km | 0.06213711922 mi |
| 0.5 km | 0.3106855961 mi |
| 1 km | 0.6213711922 mi |
| 2 km | 1.242742384 mi |
| 5 km | 3.106855961 mi |
| 10 km | 6.213711922 mi |
| 20 km | 12.42742384 mi |
| 50 km | 31.06855961 mi |
| 100 km | 62.13711922 mi |
| 500 km | 310.6855961 mi |
| 1000 km | 621.3711922 mi |
All values in this table are mathematically exact per NIST SP 811.