Health & Medicine · Fitness · Performance Metrics
Cycling Cadence Calculator
Calculate cycling cadence (RPM), speed, or gear ratio from pedal strokes, wheel size, and gear selection.
Calculator
Formula
v = speed in km/h; C = wheel circumference in metres; RPM = pedal cadence in revolutions per minute; GR = gear ratio = front chainring teeth divided by rear sprocket teeth; T_front = front chainring teeth; T_rear = rear sprocket teeth. Speed is computed by multiplying cadence by gear ratio by wheel circumference, then converting to km/h.
Source: Whitt & Wilson, 'Bicycling Science', MIT Press, 3rd ed. 2004.
How it works
Cycling speed is the product of how fast you spin the pedals (cadence in RPM), the mechanical advantage of your gearing (gear ratio), and how far the wheel travels per revolution (wheel circumference). The gear ratio is simply the number of front chainring teeth divided by the rear sprocket teeth. A 50-tooth chainring paired with a 17-tooth sprocket gives a gear ratio of 2.94, meaning the rear wheel turns 2.94 times for every single pedal revolution.
Wheel circumference is calculated from the total rolling diameter, which equals the nominal rim diameter plus twice the tyre width: C = π × (D + 2w). This is the distance the bike travels per wheel revolution. Multiplying circumference by gear ratio gives the distance travelled per pedal stroke. Multiplying further by cadence (in revolutions per second) yields speed.
This formula is used by coaches, bike fitters, and software such as Garmin Connect and TrainingPeaks to analyse ride data. It is equally applicable to road, mountain, track, and gravel cycling. Understanding how cadence interacts with gearing lets riders optimise their effort for different terrain — spinning a high cadence in a lower gear reduces muscular fatigue on climbs, while a larger gear with moderate cadence maximises speed on flat roads.
Worked example
Example: A road cyclist is riding with a 50-tooth front chainring and a 17-tooth rear sprocket. Their wheel has a 622 mm rim diameter (700c) and 25 mm tyres, and they are pedalling at 90 RPM.
Step 1 — Gear ratio: GR = 50 ÷ 17 = 2.941
Step 2 — Wheel circumference: C = π × (622 + 2 × 25) mm = π × 672 mm = 2111 mm = 2.111 m
Step 3 — Distance per pedal stroke: 2.111 m × 2.941 = 6.210 m per stroke
Step 4 — Speed: 6.210 m/stroke × 90 strokes/min × 60 min/hr ÷ 1000 m/km = 33.5 km/h (≈ 20.8 mph)
This is a typical cruising speed for a trained road cyclist on flat terrain at a comfortable aerobic cadence.
Limitations & notes
This calculator assumes a perfectly round tyre with uniform width equal to its nominal labelled width; in practice, mounted tyre diameter can vary by several millimetres depending on rim width and inflation pressure, introducing a small error in circumference. The calculation also assumes 100% drivetrain efficiency — real drivetrains lose approximately 2–5% to friction, slightly reducing actual speed. Rear wheel slip (especially on wet roads or rollers) is not accounted for. The model does not consider rider position, aerodynamic drag, gradient, or wind, so the computed speed represents mechanical output only, not real-world riding speed under resistance. For high-precision applications such as power meter calibration, measure wheel circumference with a rollout test rather than using the formula.
Frequently asked questions
What is a good cycling cadence for road cycling?
Most professional road cyclists and coaches recommend a cadence of 85–100 RPM for sustained efforts on flat terrain. Research by Lucia et al. (2001) found that elite cyclists self-select cadences around 90–100 RPM during time trials, which minimises muscle fibre recruitment stress even though it is not strictly the most mechanically efficient rate. Recreational cyclists often ride at 60–80 RPM; increasing cadence gradually toward 90 RPM can reduce knee stress and improve cardiovascular efficiency over time.
How does gear ratio affect cycling speed?
Gear ratio determines how many times the rear wheel turns for each pedal revolution. A higher gear ratio (larger front chainring or smaller rear sprocket) means more distance per pedal stroke and higher top speed at a given cadence, but requires more muscular force to push. A lower gear ratio makes pedalling easier and is suited to climbing. Speed = cadence × gear ratio × wheel circumference, so doubling the gear ratio at the same cadence doubles your speed.
What wheel diameter should I use for a 700c road bike?
The ISO/ETRTO standard rim diameter for a 700c road wheel is 622 mm. You should also enter your tyre width (e.g. 25 mm for a 25c tyre) so the calculator can compute the correct rolling circumference. A 700c × 25c tyre has an effective rolling diameter of approximately 672 mm (622 + 2 × 25) and a circumference of roughly 2111 mm. Common mountain bike sizes use a 584 mm rim (27.5") or 622 mm rim (29"), while older road bikes may use 630 mm (700b/27").
How is cadence measured on a real bike?
Cadence is most commonly measured with a dedicated cadence sensor — a small magnet mounted on the crank arm that passes a sensor fixed to the chainstay once per pedal revolution, with the sensor counting pulses per minute to compute RPM. Many modern power meters measure cadence directly from the strain gauge signal. GPS cycling computers such as Garmin Edge devices can also estimate cadence from accelerometer data without a dedicated sensor. If you do not have a sensor, you can count pedal strokes manually for 15 seconds and multiply by 4.
Does a higher cadence always mean faster cycling?
Not necessarily. Speed depends on both cadence and gear ratio — you can achieve the same speed with a high cadence in a low gear or a low cadence in a high gear. However, a higher cadence in an appropriate gear is generally more sustainable because it shifts the work burden from slow-twitch muscle fibres to the cardiovascular system, delaying muscular fatigue. For sprinting, elite track cyclists use very high gears at cadences that can briefly exceed 140–160 RPM to maximise power output.
Why does tyre width matter for the circumference calculation?
The tyre adds to the rolling diameter on both sides of the rim. A 622 mm rim fitted with a 25 mm tyre has an effective rolling diameter of 622 + 2×25 = 672 mm. Using just the rim diameter would underestimate circumference by about 8% for a 25 mm tyre, which would cause a corresponding error in the calculated speed. Wider tyres (e.g. 40 mm gravel tyres or 2.4-inch mountain bike tyres) have an even larger effect on circumference and should always be accounted for.
Last updated: 2025-07-10 · Formula verified against primary sources.