Speed/Distance/Time Calculator
Speed is distance divided by time. Formula: Speed = Distance / Time. Units: mph (miles per hour), km/h (kilometers per hour), m/s (meters per second). For example, 100 miles in 2 hours = 50 mph. Reverse calculations: Distance = Speed × Time, Time = Distance / Speed. Average speed uses total distance and total time (not average of speeds). For 60 mph for 1 hour then 40 mph for 1 hour: total 100 miles in 2 hours = 50 mph average, not (60+40)/2. Physics: velocity includes direction, speed is magnitude only.
Calculate speed, distance, or time given the other two values. Supports mph, km/h, m/s, knots, and ft/s. Convert between speed units, calculate running pace (min/km, min/mile), and see common reference speeds from walking to the speed of light.
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Inputs
Speed Unit Converter
Common Reference Speeds
| Reference | mph | km/h | m/s | knots |
|---|---|---|---|---|
| 🚶 Walking | 3.1 | 5 | 1.4 | 2.7 |
| 🏃 Running | 6.7 | 10.8 | 3 | 5.8 |
| 🚴 Cycling | 15 | 24.1 | 6.7 | 13 |
| 🚗 Car (city) | 30 | 48.2 | 13.4 | 26 |
| 🚄 High-speed train | 186.3 | 299.9 | 83.3 | 161.9 |
| ✈️ Commercial jet | 559.2 | 900 | 250 | 486 |
| 🔊 Speed of sound | 767.3 | 1,234.8 | 343 | 666.7 |
| 💡 Speed of light | 670,616,629.4 | 1.08e+9 | 299,792,458 | 582,750,421.8 |
How to Use
- Enter your value in the input field
- Click the Calculate/Convert button
- Copy the result to your clipboard
Frequently Asked Questions
- How do I calculate speed from distance and time?
- Speed equals distance divided by time: Speed = Distance ÷ Time. For example, if you travel 120 miles in 2 hours, your speed is 120 ÷ 2 = 60 mph. Make sure distance and time use compatible units — miles with hours gives mph, kilometers with hours gives km/h.
- How do I convert mph to km/h?
- Multiply mph by 1.60934 to get km/h. For example, 60 mph × 1.60934 = 96.56 km/h. To convert km/h to mph, divide by 1.60934 (or multiply by 0.621371). Quick estimate: multiply mph by 1.6 or km/h by 0.6.
- What is a knot in speed?
- A knot is one nautical mile per hour, used in maritime and aviation. 1 knot = 1.15078 mph = 1.852 km/h = 0.514444 m/s. Knots are preferred at sea and in the air because nautical miles relate directly to degrees of latitude, making navigation calculations simpler.
- How do I calculate travel time from speed and distance?
- Time equals distance divided by speed: Time = Distance ÷ Speed. For example, to travel 150 miles at 60 mph: 150 ÷ 60 = 2.5 hours (2 hours 30 minutes). Make sure distance and speed use matching units.
- What is running pace and how is it calculated?
- Running pace is time per unit distance, typically min/km or min/mile. Divide total time by distance: a 5K (5 km) in 25 minutes = 5:00 min/km pace. To convert: min/mile = min/km × 1.60934. A 5:00 min/km pace equals about 8:03 min/mile.
- What is the speed of sound and light?
- The speed of sound in air at sea level is approximately 343 m/s (767 mph or 1,235 km/h). The speed of light in a vacuum is 299,792,458 m/s (about 670,616,629 mph or 1,079,252,849 km/h). Light is roughly 874,030 times faster than sound.
- How do I convert m/s to km/h?
- Multiply m/s by 3.6 to get km/h. For example, 10 m/s × 3.6 = 36 km/h. To convert km/h to m/s, divide by 3.6. This works because 1 km = 1000 m and 1 hour = 3600 seconds: (1000 ÷ 3600) = 1/3.6.