Cycling Gear Speed Calculator
Enter your chainring and sprocket sizes, wheel circumference and cadence to instantly see your cycling speed in km/h and mph, plus gear ratio and distance per pedal revolution.
Find Your Speed from a Gear and Cadence
Cycling Gear Speed Formula
Where:
- \(z_1\) — number of teeth on the front chainring
- \(z_2\) — number of teeth on the rear sprocket (cog)
- \(i\) — gear ratio (dimensionless)
- \(C\) — wheel circumference in metres (one full wheel revolution)
- \(dev\) — distance travelled per pedal revolution, in metres
- \(cad\) — cadence in rpm (pedal revolutions per minute)
- \(v\) — bicycle speed in km/h
The formula first finds how many times the wheel turns for each pedal revolution (the gear ratio), multiplies that by the wheel circumference to get the distance covered per pedal stroke, and then scales by cadence to convert it into speed per hour.
Cycling Gear Speed – Calculation Example
Example: a road cyclist rides a 50-tooth chainring with a 14-tooth rear cog, 700×25c tyres (wheel circumference 2111 mm) and holds a cadence of 90 rpm.
\[ i = \frac{50}{14} = 3.57 \]
\[ dev = 3.57 \times 2.111\,\text{m} = 7.54\,\text{m} \]
\[ v = \frac{7.54 \times 90 \times 60}{1000} = 40.7\,\text{km/h} \]
Result: the bike travels at about 40.7 km/h (25.3 mph), covering 7.54 m (296.8 inches) per pedal revolution with a gear ratio of 3.57.
How to Use the Cycling Gear Speed Calculator
- Enter the number of teeth on your front Chainring teeth field (for example 50 for a standard big ring, 34 for a compact inner ring).
- Enter the cog size in Rear sprocket teeth — pick the sprocket you actually ride in that situation, e.g. 14.
- Fill in Wheel circumference and choose the matching unit (mm, cm, m or inch). A 700×25c road tyre is about 2111 mm; a 29″ MTB tyre is about 2288 mm.
- Enter your Cadence in rpm — the number of pedal revolutions per minute you want to sustain.
- Read your results: speed in km/h and mph, distance per pedal revolution in metres and inches, and the gear ratio.
What the Calculation Means
The calculator answers a simple question: if my legs turn the cranks at a given rate in a given gear, how fast does the bike move? The answer is fixed entirely by the drivetrain geometry — it does not depend on fitness, wind or terrain. That makes it a useful tool for comparing gears on paper before you ever ride them.
The gear ratio \(i = z_1 / z_2\) tells you how many times the rear wheel rotates for one turn of the pedals. A ratio of 3.57 means one pedal revolution spins the wheel 3.57 times. Higher ratios (bigger chainring or smaller cog) give more speed per pedal stroke but require more force; lower ratios make pedalling easier but slower — that is why you shift down for hills.
The distance per pedal revolution (sometimes called “development”, especially when measured in metres) shows how much ground one pedal stroke covers. European track and cyclo-cross racers often think in gear inches, the imperial equivalent shown in the results. At the same cadence, a bigger development simply means a higher speed.
The final speed is the development multiplied by your cadence and converted to an hourly figure. To put the numbers in context: 40.7 km/h on the flat is a hard group-ride pace, 25–30 km/h is a comfortable cruising speed for a trained cyclist, and anything under 15 km/h in a low gear typically means you are climbing. If you want to know how much power you need to actually hold that speed, try our Cycling Power Zones calculator.
Common Wheel Circumferences
| Tyre size | Typical circumference (mm) |
|---|---|
| 700×23c road | 2096 |
| 700×25c road | 2111 |
| 700×28c road | 2136 |
| 26″ MTB | 2075 |
| 29″ MTB | 2288 |
For best accuracy, measure your own wheel: roll the bike one full wheel revolution with the valve at the bottom, mark the start and end points, and measure the distance. Tyre pressure, width and tread all affect the true value.
Assumptions, Limitations and Tips
- Zero slip: the calculation assumes a perfectly efficient, non-slipping drivetrain. In reality a little chain friction exists, but it barely changes speed.
- It ignores resistance: the result is the speed your gear forces at that cadence, not the speed you can sustain. Wind, gradient, rolling resistance and your available power decide what actually happens — a 40 km/h gear is useless on a 10% climb if you cannot turn the cranks.
- Cadence matters as much as gearing: doubling your cadence doubles the speed in the same gear. Most road riders sit at 80–100 rpm; compare gears at a realistic cadence rather than a number you could only hold for seconds.
- Internal gear hubs and belt drives: enter the equivalent chainring/sprocket combination; for hub gears, calculate each hub ratio separately or use the effective development if the manufacturer publishes it.
- Use it for gear planning: before buying a new cassette or chainring, check the extremes — your lowest gear should give a development you can spin up the steepest climb you ride, and your highest should be low enough that you can still pedal downhill without spinning out.
Once you know what speed a gear produces, the next questions are about your body: can you hold that effort, and for how long? The Heart Rate Recovery and Sweat Rate calculators can help you monitor how you respond to the training those gears demand.
Frequently Asked Questions
What is a good gear ratio for everyday cycling?
There is no single "good" ratio — it depends on terrain and fitness. Commuters on flat ground typically run ratios around 2.5–3.0 (e.g. 44×16), while road riders use anything from about 1.0 in low gears for steep climbs up to 4.5+ for sprints and descents. A more practical benchmark is development: most riders are comfortable spinning gears that move the bike 5–8 m per pedal revolution at 80–100 rpm.
How do I calculate my cycling speed by hand without a calculator?
Multiply chainring teeth by wheel circumference in metres and divide by sprocket teeth to get metres per pedal revolution, then multiply by your cadence and by 60, and divide by 1000 for km/h. Example: 50×2.111 m ÷ 14 = 7.54 m; at 90 rpm that is 7.54 × 90 × 60 ÷ 1000 ≈ 40.7 km/h. For mph, divide the km/h figure by 1.609.
What are gear inches and how do they relate to this calculation?
Gear inches are an older imperial measure: chainring teeth ÷ sprocket teeth × wheel diameter in inches. A 50×14 gear on a 700c wheel (≈ 26.6" diameter with tyre) is about 95 gear inches. Gear inches describe the wheel size the gear simulates, while development (distance per pedal revolution, in metres) describes actual ground covered — the calculator shows the latter, which is easier to relate to speed.
What is the difference between gear ratio and development?
Gear ratio is the pure drivetrain number: chainring teeth ÷ sprocket teeth, with no units. It says how many times the rear wheel turns per pedal revolution. Development multiplies that ratio by the wheel circumference, so it accounts for your actual wheel size and tells you the real distance travelled per pedal stroke. Two bikes with the same ratio but different wheels (e.g. 700c vs 26") have the same ratio but different development.
What is a normal cadence, and how does it affect my speed?
Most experienced road cyclists pedal at 80–100 rpm; beginners often grind at 60–70 rpm, which strains the knees. Track sprinters can exceed 150 rpm briefly. Speed scales linearly with cadence: at the same gear, 100 rpm moves you exactly 25% faster than 80 rpm. When comparing gears, always use a cadence you can actually sustain rather than a momentary peak.
Does tyre size or wheel circumference really change the result?
Yes, directly. Switching from a 700×23c to a 29" MTB wheel (2096 vs 2288 mm) raises development by about 9%, so the same gear and cadence gives roughly 9% more speed. Even switching between 25 mm and 28 mm tyres changes the circumference by about 25 mm. For best accuracy, measure your own wheel with the roll-out method rather than relying on labelled sizes.
Can I use this calculator for a single-speed, fixed-gear or internal hub bike?
Yes. For a single-speed or fixed gear, just enter the one chainring and sprocket you have. For an internal gear hub (e.g. Rohloff, Shimano Nexus), the hub adds its own ratio on top of the chainring/sprocket ratio — calculate each hub gear separately by multiplying, or use the effective development figures from the manufacturer. Note that fixed-gear riders also care about skid patches, which depend on how the tooth counts share common factors.