Speed Converter

How to Use the Speed Converter

The Speed Converter transforms velocity measurements between all commonly used speed units. Whether you are comparing international speed limits, analyzing athletic performance, interpreting weather data, or working on physics problems, this converter handles every speed unit conversion accurately.

Supported Units

Convert between miles per hour (mph), kilometers per hour (km/h), meters per second (m/s), feet per second (ft/s), knots (nautical miles per hour), and the speed of light (c). Enter any speed value and see instant conversions to all other units.

Key Conversion Factors

1 mph = 1.60934 km/h = 0.44704 m/s = 1.46667 ft/s = 0.86898 knots. 1 km/h = 0.62137 mph = 0.27778 m/s. 1 m/s = 3.6 km/h = 2.23694 mph. 1 knot = 1.15078 mph = 1.852 km/h. The speed of light = 299,792,458 m/s ≈ 670,616,629 mph.

Common Speed References

Walking speed: 3-4 mph (5-6.5 km/h). Cycling: 12-15 mph (19-24 km/h). City speed limit: 25-35 mph (40-56 km/h). Highway speed: 60-75 mph (97-121 km/h). Commercial aircraft: 550 mph (885 km/h). Speed of sound: 767 mph (1,235 km/h). These references help you contextualize converted values.

Speed Limits Around the World

US highways: 55-85 mph. German Autobahn: no limit on some sections, advisory 130 km/h. UK motorways: 70 mph (113 km/h). Australian highways: 110-130 km/h. Understanding both mph and km/h is essential for international driving.

Knots in Aviation and Maritime

Knots (nautical miles per hour) are the standard speed unit in aviation and maritime navigation because they relate directly to latitude and longitude. One knot equals one nautical mile per hour, and one nautical mile equals one minute of latitude. This makes navigation calculations simpler.

Frequently Asked Questions

Q: How do I quickly convert mph to km/h?

A: Multiply mph by 1.6 for a close approximation. 60 mph ≈ 96 km/h (exact: 96.56). For km/h to mph, multiply by 0.6. 100 km/h ≈ 60 mph (exact: 62.14). These shortcuts work well for mental math.

Q: What is the difference between speed and velocity?

A: Speed is a scalar quantity (magnitude only), while velocity is a vector (magnitude and direction). A car going 60 mph northward has a speed of 60 mph and a velocity of 60 mph north. For unit conversion purposes, speed and velocity use the same units.

Q: Why do ships and aircraft use knots instead of mph or km/h?

A: Knots tie directly to the geographic coordinate system. Since one nautical mile equals one minute of latitude, navigators can easily calculate distances and travel times on nautical charts. This convention has been used for centuries and remains the international standard.