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How to Calculate Cycling Speed, Time, and Distance (With Examples)
Every cycling speed question is the same triangle: speed equals distance divided by time. Know any two values and the third falls out. This article walks the math, the unit conversions that trip people up, and the difference between the average speed your GPS shows and the speed you actually held.
The core formulas
- Speed = distance ÷ time (20 miles in 1.25 hours = 16 mph)
- Time = distance ÷ speed (30 miles at 15 mph = 2 hours)
- Distance = speed × time (14 mph for 90 minutes = 21 miles)
The only trap is time format. Minutes must become decimal hours before dividing: 80 minutes is 80 ÷ 60 = 1.333 hours. Riding 20 miles in 1 hour 20 minutes is therefore 20 ÷ 1.333 = 15.0 mph — not 20 ÷ 1.2. Our calculator handles the conversion automatically.
Converting between mph and km/h
Multiply mph by 1.609 to get km/h; multiply km/h by 0.621 to get mph. So 15 mph is 24.1 km/h, and the 20 km/h pace Copenhagen times its bike traffic lights to is about 12.4 mph. Pace — minutes per mile or kilometer — is just the reciprocal: 60 ÷ speed. At 15 mph you cover a mile every 4:00.
Average speed vs. moving speed
GPS computers report two numbers that diverge in cities. Moving speed pauses the clock when you stop; overall average includes red lights and coffee stops. A commuter might hold 15 mph moving speed but average 11 mph door to door. For route planning, use overall average — your meeting does not care that the light was red. Urban riders typically lose 15–25% of their moving speed to stops.
What changes your speed most
In rough order of impact: gradient (a 5% climb can halve your speed; the descent never gives it all back because of braking), wind (a 10 mph headwind costs several mph; aerodynamic drag rises with the square of airspeed), surface (gravel typically costs 2–4 mph versus pavement), drafting (riding in a group saves roughly 25–35% of the power at the same speed), and bike type (a road bike is commonly 2–4 mph faster than a mountain bike on pavement at the same effort). This is why comparing average speeds across different routes says little about fitness.
Worked planning example
You want a 2.5-hour Saturday ride and you average 13 mph on rolling terrain. Distance = 13 × 2.5 = 32.5 miles. Add a 10-minute buffer per hour for stops and you should plan a 30–32 mile loop and expect roughly 2 hours 45 minutes elapsed. Run your own numbers in the speed and calorie calculator, and see how those speeds map to effort in our training zones guide.
Keep exploring
Put these numbers to work with the free CalculateBike speed and calorie calculator, browse the cycling gear guide, or read more cycling articles. Prefer two feet to two wheels? Our sister tools CalculateSteps and CalculateRun cover walking and running.