Bicycle Gear vs Swimming Speed
The bicycle gear calculator and the swimming speed calculator both answer a version of the same question — “how fast will I travel?” — but 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 swimming speed calculator works from the simpler pair of a distance and an elapsed time, reporting average speed, pace per 100 meters, equivalent pool lengths, and constant-pace projected times. The genuine choice is which activity you are planning: a ride defined by its gearing, or a swim defined by a distance and time.
Both pages are deliberately narrow. The gear calculator describes its result as a theoretical no-slip rollout, and the swimming speed calculator includes conditions only insofar as they are present in the elapsed time. 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 swimming speed calculator takes a swim distance and elapsed seconds. Average speed is distance divided by elapsed time and converted to meters per second; pace per 100 meters is 100 divided by that speed. The chosen pool length reports equivalent lengths, which may be fractional, and projections apply the same average pace to the whole distance without adjusting for stroke. Starts, turns, rests, pool measurement, and timing method are included only insofar as they are present in the elapsed time.
Side-by-side comparison
| Feature | Bicycle Gear Calculator | Swimming Speed Calculator |
|---|---|---|
| Sport | Cycling | Swimming |
| Question answered | Speed from gearing and cadence | Speed, pace per 100 m, and projected times |
| Inputs | Chainring/cog teeth, cadence, measured rollout | Distance and elapsed seconds |
| Method | Ratio → development → speed | Distance ÷ time, converted to m/s |
| Outputs | Gear ratio, gear inches, development, theoretical speed | m/s speed, pace per 100 m, pool lengths, projections |
| Speed units | km/h and mph | Meters per second and per-100 m pace |
| Boundary | Theoretical no-slip rollout | Starts, turns, and rests only as present in elapsed time |
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 swimming speed calculator when you have a swim distance and time and want average speed, a per-100-meter pace, equivalent pool lengths, or a constant-pace projection. For a run counterpart to the swim pace, the running pace calculator and the pace converter calculator handle pace, time, and distance in miles and kilometers. Choose based on the sport and the inputs you can measure consistently, and treat both results as planning arithmetic with no performance claim.
Where to start
- Bicycle gear calculator — gear ratio, gear inches, development, and cadence-based speed from a measured wheel.
- Swimming speed calculator — average speed, pace per 100 meters, pool lengths, and projected times.
Informational note: This page is an educational comparison. The bicycle gear result is a theoretical no-slip rollout and the swimming result is distance-over-time arithmetic from entered values. Neither calculator provides a performance-level, training, fitness, or medical conclusion.