Cycling Speed from Cadence
Gear ratio is front teeth over rear teeth. One pedal turn spins the wheel that many times, and each wheel turn covers its circumference. Multiply by rpm and sixty minutes for km/h.
Your numbers
Speed (km/h)
34.3km
Distance (km)
6.72m
Time (min)
1.75min
Formula
Speed (km/h) = Wheel circumference (cm) × Gear ratio × Cadence (rpm) × 60 ÷ 100000
A 700×25c tyre rolls about 210 cm. Width and pressure shift that by a few centimetres, so roll the wheel out if you need precision.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Wheel circumference (cm) (cm)How far the wheel travels in one full turn. | 210 | 100 ~ 260 |
| Cadence (rpm) (rpm)Pedal revolutions per minute. | 85 | 30 ~ 150 |
| Gear ratioFront chainring teeth divided by rear sprocket teeth. | 3.2 | 0.5 ~ 6 |
Step by step
Quick reference table
Results when only Wheel circumference (cm) (cm) changes and everything else stays put.
| Wheel circumference (cm) (cm) | Speed (km/h) (km) | Distance (km) (m) | Time (min) (min) |
|---|---|---|---|
| 105 | 17.1 | 3.36 | 3.5 |
| 158 | 25.8 | 5.06 | 2.33 |
| 210 | 34.3 | 6.72 | 1.75 |
| 260 | 42.4 | 8.32 | 1.41 |
What each result means
| Result | At default values |
|---|---|
| Speed (km/h) (km)How many kilometres you cover in an hour. | 34.3 |
| Distance (km) (m)Distance measured in kilometres. | 6.72 |
| Time (min) (min)The time it took, in minutes. | 1.75 |
Common mistakes
A 700×25c tyre rolls about 210 cm. Width and pressure shift that by a few centimetres, so roll the wheel out if you need precision.
Glossary
- Wheel circumference (cm)
- How far the wheel travels in one full turn.
- Cadence (rpm)
- Pedal revolutions per minute.
- Gear ratio
- Front chainring teeth divided by rear sprocket teeth.
- Speed (km/h)
- How many kilometres you cover in an hour.
- Distance (km)
- Distance measured in kilometres.
- Time (min)
- The time it took, in minutes.
Frequently asked questions
Q. How is Cycling Speed from Cadence calculated?
Speed (km/h) = Wheel circumference (cm) × Gear ratio × Cadence (rpm) × 60 ÷ 100000 — Gear ratio is front teeth over rear teeth. One pedal turn spins the wheel that many times, and each wheel turn covers its circumference. Multiply by rpm and sixty minutes for km/h.
Q. Can you walk through an example?
With Wheel circumference (cm) 210cm, Cadence (rpm) 85rpm, Gear ratio 3.2, the answer is Speed (km/h) 34.3km.
Q. What do I need to enter?
Enter Wheel circumference (cm), Cadence (rpm), Gear ratio. The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Wheel circumference (cm) (cm) moves the answer to Wheel circumference (cm) (cm) 105 → Speed (km/h) (km) 17.1 and Wheel circumference (cm) (cm) 260 → Speed (km/h) (km) 42.4. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
A 700×25c tyre rolls about 210 cm. Width and pressure shift that by a few centimetres, so roll the wheel out if you need precision.
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