Speed Converter
Free speed unit converter. Convert between km/h, mph, m/s, knots, and ft/s. Real-time conversions for velocity and speed measurements.
Convert between different speed units including km/h, mph, m/s, knots, and ft/s.
What is Speed and Why Convert Between Units?
Speed is the distance traveled per unit of time. Different regions and industries use different units to measure speed. Understanding how to convert between them is essential for international communication, travel planning, and scientific work.
The most common speed units are:
- Kilometers per hour (km/h): Used in most of the world, especially road traffic
- Miles per hour (mph): Used in the United States and United Kingdom for road speed
- Meters per second (m/s): The SI base unit, used in physics and engineering
- Knots: Used in maritime and aviation contexts
- Feet per second (ft/s): Used in some engineering applications
Formula: Speed = Distance ÷ Time
How to Use the Speed Converter
- Enter the speed value you want to convert
- Select the current unit (from unit)
- Select the target unit (to unit)
- The converter displays the result and shows conversions to all other units automatically
The converter uses precise conversion factors based on SI standards and NIST specifications.
Examples
Example 1: Highway Speed
- You’re driving at 120 km/h. How fast is that in mph?
- 120 km/h ÷ 1.609 = 74.6 mph
Example 2: Running Speed
- A runner maintains 6 m/s. What’s the speed in km/h?
- 6 m/s × 3.6 = 21.6 km/h
Example 3: Aircraft Speed
- A small aircraft cruises at 200 knots. What’s the speed in km/h?
- 200 knots × 1.852 = 370.4 km/h
FAQ
Q: Why are knots used for ships and planes? A: Knots represent nautical miles per hour, which relates to latitude and longitude coordinates used in navigation. This makes it practical for maritime and aviation professionals.
Q: How does the SI standard define speed? A: The SI base unit for speed is meters per second (m/s). All other speed units are derived from or converted to this base unit.
Q: Is mph still officially used? A: Yes, the United States and United Kingdom officially use mph for road traffic. Most other countries use km/h following the metric system.
Q: What’s the relationship between m/s and km/h? A: 1 m/s = 3.6 km/h. This is because 1 m/s means 1 meter per second, which equals 60 meters per minute, or 3,600 meters per hour, or 3.6 kilometers per hour.
Q: How accurate are the conversions? A: The converter uses NIST-verified conversion factors and maintains numerical precision to 6 decimal places for scientific accuracy.