How to Convert Speed Units
Convert between different speed units instantly. Our converter handles miles per hour, kilometers per hour, meters per second, knots, and more-useful for driving, running, sailing, and scientific applications.
Understanding Speed Units
Speed measures how fast something moves-the distance traveled per unit of time. Common units include mph (miles per hour) in the US, km/h (kilometers per hour) internationally, and knots for nautical/aviation use.
Common Speed Conversions
Key relationships: 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.
Example:
To convert 60 mph to km/h: 60 × 1.609 = 96.5 km/h. To convert 100 km/h to mph: 100 × 0.621 = 62.1 mph.
Common Use Cases
Real-world applications for this calculator
Driving
Convert speed limits when driving in countries using different units (mph vs km/h).
Running & Fitness
Convert between pace (min/mile or min/km) and speed for training analysis.
Aviation & Sailing
Convert between knots and other speed units for navigation purposes.
Tips
- Quick conversion: multiply mph by 1.6 to estimate km/h.
- Highway speeds: 60 mph ≈ 97 km/h, 70 mph ≈ 113 km/h.
- Running: a 10 min/mile pace ≈ 6 mph ≈ 9.7 km/h.
Frequently Asked Questions
How do I convert mph to km/h?
Multiply mph by 1.609 to get km/h. For example, 65 mph = 65 × 1.609 = 104.6 km/h. For a quick estimate, multiply by 1.6.
How do I convert km/h to mph?
Multiply km/h by 0.621 to get mph. For example, 100 km/h = 100 × 0.621 = 62.1 mph. For a quick estimate, multiply by 0.6.
What is a knot?
A knot is a unit of speed equal to one nautical mile per hour. 1 knot = 1.151 mph = 1.852 km/h. It's commonly used in maritime and aviation contexts.
How fast is the speed of sound?
The speed of sound at sea level is approximately 767 mph (1,235 km/h or 343 m/s). This is called Mach 1. The exact speed varies with temperature and altitude.