Speed Converter
General
0
Formula
01
What this converter does
This converter turns kilometres per hour into miles per hour and back instantly. It also covers m/s, ft/s and knots — every pair uses an exact factor. Type a value, pick your units, and read the result as you type.
One mile per hour equals 1.60934 km/h, so km/h × 0.621 gives mph. Unit definitions follow NIST.
02
The units it covers
Every speed unit converts through metres per second with a fixed ratio.
View all units & their values
| Unit | Symbol | Value | Mainly used |
|---|---|---|---|
| Metre per second | m/s | 1 | SI unit, physics |
| Kilometre per hour | km/h | 0.277778 | Road speed, most of world |
| Mile per hour | mph | 0.44704 | Road speed, US/UK |
| Foot per second | ft/s | 0.3048 | US engineering |
| Knot | kn | 0.514444 | Marine & aviation |
03
The formula
Each unit has a fixed value in metres per second, so converting goes through m/s once:
Conversion
result = value × factor_from ÷ factor_toWhere:
- value = the number you typed
- factor_from = the “from” unit’s value in m/s
- factor_to = the “to” unit’s value in m/s
04
Worked example
Convert 100 km/h to mph.
Step 1 · The factors
km/h = 0.277778 m/s · mph = 0.44704 m/sStep 2 · Convert
100 × 0.277778 ÷ 0.44704 = 62.14 mphSo 100 km/h is about 62.1 mph.
05
The units in this example
Kilometre per hoursymbol: km/h
The metric unit of road speed, used in most of the world.
Common speed conversions
- 1 km/h = 0.6214 mph
- 1 km/h = 0.2778 m/s
- 100 km/h = 62.14 mph
- 1 km/h = 0.54 kn
Mile per hoursymbol: mph
The imperial unit of road speed, used in the US and UK.
Common speed conversions
- 1 mph = 1.6093 km/h
- 1 mph = 0.447 m/s
- 60 mph = 96.56 km/h
- 1 mph = 0.869 kn
06
FAQ
QHow many mph is 100 km/h?
One hundred km/h is about 62.14 mph.
QHow do I convert km/h to mph?
Multiply the km/h figure by 0.6214.
08