Speed Converter
Convert speeds precisely – for travel, sports, weather and shipping
- Updated
You can type in either field.
Result in Miles per hour (mph)
0.6213712mph
0.62137121 km/h equals 0.6213712 mph.
In all units
Tap a unit to make it the target.
German urban speed limit (50 km/h) is about 50 times your value.
- Your value0.6213712 mph
- German urban speed limit (50 km/h)31.07 mph
- German motorway advisory speed (130 km/h)80.78 mph
- Sound in air (20 °C)767.3 mph
- Light in a vacuum670,600,000 mph
Bars on a logarithmic scale, values rounded.
How this was calculated
Both units are converted via the base unit m/s: 1 km/h = 0.2777777778 m/s and 1 mph = 0.44704 m/s.
RZ-26 · headon.pro
Speed units: overview and applications
From km/h on the road to knots in aviation
The SI unit of speed is metres per second (m/s). In everyday life, however, kilometres per hour (km/h) is the most common unit for road traffic, weather services and sports in Germany and most countries. On the roads in the US and the UK, miles per hour (mph) is used instead. The conversion is simple: 1 mph = 1.60934 km/h. As a rule of thumb for travellers: 60 mph is just under 100 km/h, and 100 km/h is about 62 mph.
In shipping and aviation, the knot (kn) is the worldwide standard. One knot equals one nautical mile per hour (1.852 km/h). This unit is used consistently on nautical charts and in flight plans worldwide, which makes international navigation much easier. A passenger aircraft cruising at around 10,000 m typically flies at 450–500 knots, which corresponds to 833–926 km/h. Closer to the ground, cruising speed drops significantly due to higher air resistance.
In physics and engineering, m/s is commonly used because it is the direct SI unit. Laws of motion such as Newton’s second law (F = m × a) use m/s² as the unit of acceleration. The speed of light, c = 299,792,458 m/s, is one of the fundamental constants of nature and has served since 1983 as the basis for the definition of the metre.
In everyday weather reports, wind speeds appear in km/h, m/s and on the Beaufort scale (Bft). Beaufort 6 (strong breeze) corresponds to about 39–49 km/h (10.8–13.8 m/s), while Beaufort 12 (hurricane) means over 117 km/h (over 32.7 m/s). Marine weather services and maritime apps usually give wind speed in knots: 20 knots of wind equals 37 km/h, or 10.3 m/s.
In sports and fitness tracking, converting between km/h and pace (min/km) matters: a runner averaging 10 km/h runs a pace of 6:00 min/km. Cycling apps commonly use km/h, and GPS watches can usually switch between km/h, mph and min/km. In swimming, speed is often given in seconds per 100 metres, which requires its own conversion logic. Our converter covers all common speed units for travel, sports, navigation and science, and delivers instant, precise results.
Important reference speeds
Comparison speeds
- 100 km/h = 62.1 mph
- German rural-road speed
- 130 km/h = 80.8 mph
- Recommended motorway speed
- 900 km/h = 560 mph
- Airliner cruising speed
- 20 kn = 37 km/h
- Typical container ship
- 343 m/s = 1,235 km/h
- Speed of sound (20°C air)
- 299,792,458 m/s
- Speed of light in a vacuum
Calculation examples
- Formula
- km/h ÷ 1.60934 = mph
- Value
- 100 km/h
- Divisor
- 1.60934
- Result
- 62.14 mph
- Formula
- m/s × 3.6 = km/h
- Value
- 30 m/s
- Factor
- 3.6
- Result
- 108 km/h
- Formula
- kn × 1.852 = km/h
- Value
- 25 kn
- Factor
- 1.852
- Result
- 46.3 km/h
Frequently asked questions about the speed converter
Everything about km/h, mph, m/s and knots
How do I convert km/h to mph?
Formula: mph = km/h ÷ 1.60934. Example: 100 km/h = 100 ÷ 1.60934 = 62.14 mph. Rule of thumb: km/h × 0.6 gives a good approximation. Typical comparisons: 50 km/h (urban area) = 31.1 mph, 100 km/h (rural road) = 62.1 mph, 130 km/h (motorway) = 80.8 mph.
How do I convert mph to km/h?
Formula: km/h = mph × 1.60934. Example: 60 mph = 60 × 1.60934 = 96.56 km/h. US speed limits: 25 mph (residential) ≈ 40 km/h, 55 mph (rural road) ≈ 88 km/h, 65–75 mph (interstate) ≈ 105–121 km/h.
What is a knot (kn) and how many km/h is that?
1 knot = 1 nautical mile per hour = 1.852 km/h. Knots are the standard unit in shipping and aviation worldwide. A ship travelling at 20 knots is doing 37 km/h. A passenger aircraft typically cruises at 450–500 knots (833–926 km/h).
How do I convert m/s to km/h?
Formula: km/h = m/s × 3.6. Example: 10 m/s = 10 × 3.6 = 36 km/h. Conversely: m/s = km/h ÷ 3.6. The factor 3.6 comes from 1 km = 1,000 m and 1 h = 3,600 s: (1,000 ÷ 3,600 = 0.2778, so 1 km/h = 0.2778 m/s).
How fast is Beaufort force 8 in km/h?
Beaufort force 8 corresponds to 62–74 km/h (gale, 17.2–20.7 m/s, 33.5–40.3 kn). The Beaufort scale ranges from 0 (calm) to 12 (hurricane force, over 117 km/h). The conversion: wind speed in m/s ≈ 0.836 × B^(3/2), where B is the Beaufort force.