Bicycle Gear vs Running Pace
The bicycle gear calculator and the running pace calculator both answer a version of the same question — “how fast will I travel?” — but they get there from completely different inputs. The bicycle gear calculator derives a theoretical speed from the machine: chainring and rear-cog tooth counts, cadence, and a measured loaded wheel rollout. The running pace calculator works from the simpler pair of a distance and a time, solving the missing quantity from the other two. The genuine choice is which activity you are planning: a ride defined by its gearing, or a run defined by a target pace or finish time.
Both pages are deliberately narrow. The gear calculator describes its result as a theoretical no-slip rollout, and the pace calculator leaves stops, course measurement, terrain, and conditions outside the arithmetic. Neither assigns a performance level or prescribes training.
What each calculator does
The bicycle gear calculator starts with a measured wheel rollout: inflate the tire to riding pressure, mark tire and ground at the valve, roll the loaded bicycle straight for one complete wheel revolution, and enter the distance between the marks as circumference. Gear ratio is chainring teeth divided by rear-cog teeth. Development is measured circumference times that ratio; effective diameter is circumference divided by π, and gear inches is that diameter in inches times the ratio. Theoretical speed is development times cadence, converted from meters per minute to km/h and mph. Tire slip, dynamic deformation, drivetrain loss, wind, grade, acceleration, and rider power are not modeled.
The running pace calculator lets you choose whether to solve pace, elapsed time, or distance, then enter the other two quantities. It works in raw seconds and uses the exact international mile conversion of 1.609344 kilometers, so it reports pace per mile or per kilometer, estimates a time from a distance and a target pace, or checks how far a block of time at a steady pace covers.
Side-by-side comparison
| Feature | Bicycle Gear calculator | Running Pace calculator |
|---|---|---|
| Sport | Cycling | Running |
| Question answered | Speed from gearing and cadence | Pace, time, or distance from the other two |
| Inputs | Chainring/cog teeth, cadence, measured rollout | Any two of pace, time, and distance |
| Method | Ratio → development → speed | Distance ÷ time in raw seconds |
| Speed units | km/h and mph | Per mile and per kilometer |
| Key outputs | Gear ratio, gear inches, development, theoretical speed | The missing one of pace, time, or distance |
| Boundary | Theoretical no-slip rollout | Stops and terrain outside the arithmetic |
When to use which
Use the bicycle gear calculator when you are working with the drivetrain itself — comparing chainring and cog combinations, checking gear inches or development, or estimating what speed a chosen cadence produces over your measured wheel. Use the running pace calculator when you are planning a run in time-per-distance terms, converting between miles and kilometers, or solving for any one of pace, time, or distance from the other two. For a specific race, the half marathon pace calculator extends the pace idea to the standard 21.0975 km distance with even cumulative splits; for switching between pace and speed units, the pace converter calculator handles min/km, min/mile, km/h, and mph.
Where to start
- Bicycle gear calculator — gear ratio, gear inches, development, and cadence-based speed from a measured wheel.
- Running pace calculator — solve pace, time, or distance in miles or kilometers.