Home › Unit Conversion › Kilometers per hour to Miles per hour
Kilometers per hour to Miles per hour (km/h to mph)
Convert kilometers per hour to miles per hour: 1 km/h = 0.621371 mph. Exact conversion factor, formula, 22-row table and worked examples, with JSON API and MCP access.
Formula
1 km/h = 0.621371 mph
miles per hour = kilometers per hour × 0.6213711922 — reverse: kilometers per hour = miles per hour × 1.609344
The factor is derived from the SI definitions of both units (base unit: m/s) as listed in NIST SP 811; results on this page are shown to 6 significant figures, the API returns up to 12.
Worked examples
- 5 km/h = 3.10686 mph
- 12.5 km/h = 7.76714 mph
- 100 km/h = 62.1371 mph
Kilometers per hour to miles per hour conversion table
| Kilometers per hour (km/h) | Miles per hour (mph) |
|---|---|
| 1 | 0.621371 |
| 2 | 1.24274 |
| 3 | 1.86411 |
| 4 | 2.48548 |
| 5 | 3.10686 |
| 6 | 3.72823 |
| 7 | 4.3496 |
| 8 | 4.97097 |
| 9 | 5.59234 |
| 10 | 6.21371 |
| 15 | 9.32057 |
| 20 | 12.4274 |
| 25 | 15.5343 |
| 30 | 18.6411 |
| 40 | 24.8548 |
| 50 | 31.0686 |
| 75 | 46.6028 |
| 100 | 62.1371 |
| 200 | 124.274 |
| 250 | 155.343 |
| 500 | 310.686 |
| 1000 | 621.371 |
FAQ
How many miles per hour are in one kilometer per hour?
1 km/h = 0.621371 mph. The factor comes from the SI definitions of both units (NIST SP 811 / BIPM), so it is exact or correct to at least 10 significant figures.
What is the formula to convert kilometers per hour to miles per hour?
Multiply the value in kilometers per hour by 0.6213711922: miles per hour = kilometers per hour × 0.6213711922. For example, 5 km/h = 3.10686 mph.
How do I convert miles per hour back to kilometers per hour?
Multiply by the inverse factor 1.609344 (kilometers per hour = miles per hour × 1.609344), or use the miles per hour-to-kilometers per hour page.
Related conversions
- Miles per hour to kilometers per hour (reverse)
- Speed Converter — all speed units in one tool
- Meters per second to Kilometers per hour
- Kilometers per hour to Meters per second
- Meters per second to Miles per hour
- Miles per hour to Meters per second
- Knots to Kilometers per hour
- Kilometers per hour to Knots
- Knots to Miles per hour
- Miles per hour to Knots
Machine access
- API:
GET https://tttkmbb.com/api/v1/convert?value=5&from_unit=km%2Fh&to_unit=mph - MCP: server
https://tttkmbb.com/mcp, toolconvert_unitswith{"value":5,"from_unit":"km/h","to_unit":"mph"} - Markdown: https://tttkmbb.com/conversion/kmh-to-mph.md · JSON: https://tttkmbb.com/conversion/kmh-to-mph.json (add
?value=for a result) · Units: /api/v1/units?quantity=speed - OpenAPI operationId:
convert_units. Freshness:static. Authentication: none.