Speed Converter
Convert between mph, km/h, m/s, knots, and ft/s.
Try a common conversion
1 km/h = 0.6213711922 mph
| Kilometers per Hour (km/h) | Miles per Hour (mph) |
|---|---|
| 1 | 0.6213711922 |
| 2 | 1.242742384 |
| 5 | 3.106855961 |
| 10 | 6.213711922 |
| 15 | 9.320567884 |
| 20 | 12.42742384 |
| 25 | 15.53427981 |
| 50 | 31.06855961 |
| 75 | 46.60283942 |
| 100 | 62.13711922 |
| 150 | 93.20567884 |
| 200 | 124.2742384 |
| 250 | 155.3427981 |
| 500 | 310.6855961 |
| 1,000 | 621.3711922 |
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Helpful answers
Frequently asked questions
- What speed units can I convert between?
- Meters per second (m/s), kilometers per hour (km/h), miles per hour (mph), knots, and feet per second (ft/s). These cover automotive, aviation, marine, and scientific use cases.
- What are common speed conversions?
- 1 mph = 1.609 km/h, 1 km/h = 0.621 mph, 1 knot = 1.151 mph = 1.852 km/h, 1 m/s = 3.6 km/h = 2.237 mph.
- What is a knot?
- A knot is one nautical mile per hour (1.852 km/h). It is the standard unit for maritime and aviation speed. The name comes from the historical practice of measuring ship speed by counting knots in a rope.
Worked examples
Speed conversions go wrong in two places: confusing km/h with mph, and treating a knot as a mile per hour. These worked examples show the arithmetic so you can check any result by hand.
A 65 mph speed limit in km/h
Multiply by 1.609344: 65 × 1.609344 = 104.61 km/h. Rounded, that is about 105 km/h.
A 100 km/h limit in mph
Divide by 1.609344: 100 ÷ 1.609344 = 62.14 mph, so roughly 62 mph.
A boat doing 20 knots
A knot is one nautical mile per hour, exactly 1.852 km/h. 20 knots = 37.04 km/h, or about 23 mph.
A sprinter at 10 m/s
A metre per second is 3.6 km/h (3,600 seconds in an hour divided by 1,000 metres in a kilometre). 10 m/s = 36 km/h, which is about 22.4 mph.
Navigation
When to use this
You are driving in Europe and the speed limit sign says 130 — that is km/h, but how fast is that in mph? Or you are reading a weather report about wind speeds in knots and want to understand the real-world impact in miles per hour. Or a physics problem gives velocity in meters per second and you need km/h. Speed conversion comes up in driving abroad, aviation, sailing, meteorology, physics, and sports.
Use km/h to mph for a speed shown in kilometers per hour, mph to km/h for miles per hour, or knots for nautical speeds. The labels kph, kmh, and km/h refer to the same unit. This converter handles all of these plus meters per second (the SI unit) and feet per second. The key relationships: 1 mph = 1.609 km/h, 1 knot = 1.151 mph, and 1 m/s = 3.6 km/h.
Good to know
Quick mph-to-km/h estimate: multiply by 1.6. 60 mph is about 97 km/h. 100 km/h is about 62 mph. For most driving situations, these estimates are close enough to understand speed limit signs in another country.
A knot is one nautical mile per hour. Knots are used in aviation and maritime because they tie directly to the latitude/longitude coordinate system. One knot = 1.852 km/h = 1.151 mph. Airspeed is measured relative to the surrounding air; ground speed is measured relative to the ground. Converting the unit does not change that reference.
Feet per second is common in engineering. One foot per second equals exactly 0.3048 m/s, or about 1.09728 km/h and 0.681818 mph. It is useful for projectile motion, flow rates, and US engineering specifications.
Meters per second puts everyday speeds in perspective. Walking speed is about 1.4 m/s. A fast sprint is about 10 m/s. Highway driving at 70 mph is about 31 m/s. The speed of sound at sea level is about 343 m/s. Using m/s helps you understand the physics behind familiar experiences.
Quick Reference
| MPH | KM/H | M/S | Knots | Context |
|---|---|---|---|---|
| 3.1 | 5 | 1.4 | 2.7 | Walking |
| 12.4 | 20 | 5.6 | 10.8 | Cycling |
| 30 | 48.3 | 13.4 | 26.1 | City driving |
| 60 | 96.6 | 26.8 | 52.1 | Highway driving |
| 70 | 112.7 | 31.3 | 60.8 | US interstate limit |
| 80.8 | 130 | 36.1 | 70.2 | EU motorway limit |
| 100 | 160.9 | 44.7 | 86.9 | Fast driving |
| 767 | 1,235 | 343 | 667 | Speed of sound |
| 0.682 | 1.097 | 0.3048 | 0.593 | 1 foot per second |