The speed, distance and time formulas
Speed = Distance ÷ Time
Distance = Speed × Time
Time = Distance ÷ Speed
Example: driving 150 miles in 2 hours 30 minutes is 150 ÷ 2.5 = 60 mph (96.56 km/h). At 60 mph, 210 miles takes 3 h 30 min.
Tips
- Convert minutes to hours before dividing: 30 minutes is 0.5 h, 45 minutes is 0.75 h.
- This gives the average speed over the whole trip, including stops, if you use the total time.
- 1 mile = 1.609 km; 60 mph ≈ 97 km/h; 100 km/h ≈ 62 mph.
For running, the pace calculator works in minutes per mile; for trip fuel, try the fuel cost calculator.
Frequently asked questions
How do you calculate average speed?
Divide the total distance by the total time. 120 miles in 2 hours is 60 mph.
How long does it take to drive 100 miles at 60 mph?
1 hour 40 minutes: 100 ÷ 60 = 1.667 hours.
How do I convert mph to km/h?
Multiply by 1.609. 65 mph is about 105 km/h.
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