Cadence to Speed Calculator
Convert your pedaling cadence into actual riding speed using your gear ratio and wheel size. Useful for cyclists optimizing gearing on road, gravel, or track bikes.
About this calculator
Cycling speed depends on three factors: how fast you pedal (cadence in RPM), how far each pedal revolution moves the chain relative to the rear wheel (gear ratio), and how far the wheel travels per rotation (wheel circumference). The formula is: Speed (km/h) = (cadence × gear ratio × wheel circumference × 60) / 1,000,000. Cadence is measured in revolutions per minute, gear ratio is the number of front chainring teeth divided by rear cog teeth, and wheel circumference is in millimeters. Multiplying by 60 converts minutes to hours, and dividing by 1,000,000 converts millimeters to kilometers. A higher cadence or larger gear ratio both increase speed proportionally, while a larger wheel circumference also boosts speed for any given cadence and gear combo.
How to use
Suppose you pedal at 90 RPM, run a gear ratio of 2.5 (e.g. 50-tooth chainring ÷ 20-tooth cog), and your wheel circumference is 2,100 mm. Plug into the formula: Speed = (90 × 2.5 × 2,100 × 60) / 1,000,000 = 28,350,000 / 1,000,000 = 28.35 km/h. So at 90 RPM in that gear with a standard 700c road tire, you would be traveling at approximately 28.4 km/h. Increasing your cadence to 100 RPM in the same gear would push your speed to about 31.5 km/h.
Frequently asked questions
How does gear ratio affect cycling speed at the same cadence?
Gear ratio directly multiplies your effective speed — doubling the gear ratio doubles your speed at any given cadence. It is calculated by dividing the number of teeth on your front chainring by the teeth on the rear cog. A 50/17 setup gives a ratio of about 2.94, while a 34/28 climbing gear gives only 1.21. Choosing a larger (harder) gear lets you cover more ground per pedal stroke but requires more force.
What is a good cycling cadence for road cycling?
Most road cycling coaches recommend a cadence between 85 and 100 RPM for sustained efforts, as this range minimizes muscular fatigue and distributes load to the cardiovascular system. Beginner cyclists often naturally settle around 60–70 RPM, which places more strain on the legs. Tour de France riders like Lance Armstrong famously trained at cadences above 100 RPM. Finding your optimal cadence is personal and may take weeks of practice to establish.
How do I measure my bike's wheel circumference accurately?
The most accurate method is the rollout test: mark a point on your tire, roll the bike forward one full wheel revolution, and measure the distance between the two marks on the ground. Alternatively, measure the outer tire diameter and multiply by π (3.14159). A standard 700×25c road tire has a circumference of roughly 2,105 mm, while a 29-inch MTB tire is around 2,288 mm. Manufacturer charts are a quick reference but may vary slightly from your actual inflated tire size.