Bike Cadence Calculator - Speed and Pedal RPM
Use the bike cadence calculator to find pedal RPM from speed or predict speed from cadence using chainring, cog, wheel diameter, and tire thickness.
Bike Cadence Calculator
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What Is the Bike Cadence Calculator?
Bike cadence measures how fast you turn the pedals in revolutions per minute, and it is one of the most useful numbers a cyclist can track alongside speed. This bike cadence calculator converts that pedaling rhythm into context by relating your RPM to the bike's gear ratio, wheel size, and tire thickness, so you can predict speed from cadence or back-solve cadence from a known speed. Use it to plan an endurance ride, dial in a climbing gear, or check whether your trainer cadence matches the speed you will hold outdoors.
- • Road cyclists tuning endurance pace: Confirm that a target 90 RPM cadence produces the 18-20 mph cruising speed you want on the flats, and use that speed as a pacing anchor.
- • Mountain bikers sizing a climbing gear: Match a 22×42 climbing gear to the 60-70 RPM cadence that keeps you seated on steep pitches.
- • Indoor trainers validating outdoor pacing: Convert a trainer cadence of 85 RPM into the outdoor speed you can expect on a 700c or 29er wheel.
The same RPM produces very different speeds depending on whether you are turning a 50×11 sprint gear on a 700c wheel or a 22×42 climbing gear on a 29er, so the calculator makes that relationship explicit.
If your real question is about chainring and cassette choices rather than cadence itself, the Bicycle Gear Ratio Calculator works through the same chainring, cog, and wheel size inputs to show you the gear inches and meters of development for each gear.
How the Bike Cadence Calculator Works
The calculator uses the standard bicycle drivetrain relationship that links pedal speed, gear ratio, and rolling circumference. Enter any four of speed, cadence, gear ratio, or wheel circumference and the formula returns the missing value, with all distances normalised to meters per minute.
- speedMph: Bicycle speed in miles per hour, converted to meters per minute by multiplying by 0.44704 × 60.
- cadenceRpm: Pedaling cadence in revolutions per minute, the value the calculator either reads or returns.
- chainringTeeth: Number of teeth on the front chainring; combined with the rear cog to form the gear ratio.
- cogTeeth: Number of teeth on the selected rear cog from the cassette.
- wheelDiameter: Rim diameter in inches, before the tire is mounted.
- tireThickness: Inflated tire thickness in inches on each side; doubled internally to add to the rim diameter.
The same formula is reversible, so feeding in cadence returns the speed and lets the calculator support both directions from one relationship.
Road bike at 18 mph on a 50×17 with a 700c wheel
Speed 18 mph, chainring 50 teeth, rear cog 17 teeth, wheel diameter 28 in, tire thickness 1.0 in.
Wheel outside diameter 30 in, circumference 2.394 m. Gear ratio 2.94. Cadence = (18 × 0.44704 × 60) ÷ (2.394 × 2.94) ≈ 68.6 RPM.
About 69 RPM, classed as Endurance for a 18 mph cruise on the 700c road wheel.
That is a comfortable endurance cadence for long group rides where you want to stay seated and keep fatigue low.
According to Wikipedia bicycle wheel reference, the rolling circumference of a bicycle wheel equals π times the outside diameter, where the outside diameter is the rim diameter plus twice the inflated tire thickness.
If you are matching cadence to a target wattage, the Cycling Power-to-Weight Ratio Calculator translates your FTP and body weight into W/kg, which is the ratio that decides whether a 90 RPM cadence actually moves you uphill at a competitive pace.
Key Concepts Explained
Four ideas come up every time cyclists compare cadence, gear ratio, and speed, and they are worth understanding before you treat the calculator's output as gospel.
Pedal cadence (RPM)
Pedal cadence is the number of full pedal revolutions per minute, captured by a cadence sensor or counted against a wall clock. It is the input most cyclists have direct control over through gear choice and effort.
Gear ratio
Gear ratio is the chainring tooth count divided by the rear cog tooth count. A higher ratio means the wheel turns more times for every pedal revolution, raising speed at the same cadence.
Wheel circumference
Wheel circumference is the rolling distance covered in one wheel revolution. It depends on the rim diameter plus twice the tire thickness, and sets the linear distance each gear ratio converts into travel per pedal stroke.
Cadence-to-speed conversion
Cadence to speed is the reverse of the bike's gear relationship: speed equals cadence times the gear ratio times the wheel circumference. The two directions are the same formula, just rearranged.
Treat the four concepts as a chain: cadence times gear ratio gives wheel revolutions, and wheel revolutions times circumference gives distance, so any break in the chain changes the final speed.
If you want to attach a power number to your cadence choice, the Cycling FTP Calculator converts a 20-minute or 8-minute test into an FTP you can target in watts.
How to Use This Calculator
The calculator is built to mirror how a cyclist actually answers these questions, so the input order matches the order you would naturally follow when reading from a bike computer.
- 1 Choose the calculation direction: Pick Speed → Cadence if you have a speed reading and want the implied RPM, or Cadence → Speed if your cadence sensor is the trusted number.
- 2 Enter the value you already know: Type the speed in mph or the cadence in RPM, and leave the other field at zero so the calculator focuses on the direction you chose.
- 3 Fill in the drivetrain details: Enter your chainring teeth and rear cog teeth, then set the wheel diameter in inches (28 for 700c, 24.5 for 29er, 22 for 26 inch MTB) and tire thickness per side.
- 4 Read the cadence or speed result: The primary panel shows the value you asked for, with a metric speed in km/h and a plain-language cadence label to help interpret the number.
- 5 Check gear ratio and wheel circumference: Use the secondary results to see the gear ratio and rolling circumference, confirming the inputs match the bike you ride.
- 6 Reset and try a different gear: Press Reset to return to defaults, then change the rear cog to simulate shifting and see how cadence and speed trade off.
Practical example: planning a 50 mile ride
Set Speed → Cadence, enter 17 mph, leave cadence at 0, then chainring 50, cog 17, wheel 28, tire 1.0.
You will see about 65 RPM, classed as Endurance, confirming the 50×17 gear is an easy spin for the back half of a long ride.
Once you know the cadence and speed you will hold, the Calories Burned Biking Calculator takes the same ride data and turns it into an estimated calorie burn, which is useful for fuelling longer endurance efforts.
Benefits of Using This Calculator
These benefits show up most clearly when the calculator is used as a planning tool before a ride rather than as a curiosity afterwards.
- • Pick the right gear before the climb: Test a 34×32 climbing gear in the calculator and see the 60-70 RPM cadence it produces at your expected climbing speed.
- • Translate trainer cadence to outdoor speed: Convert the 85 RPM you hold on the trainer into the outdoor speed you will see, accounting for your real wheel and tire setup.
- • Standardise cadence across different bikes: Compare the same cadence on a 700c road bike, a 27.5 hybrid, and a 29er mountain bike so you can ride the same perceived effort at different actual speeds.
- • Diagnose suspicious speed readings: If your bike computer shows a speed that does not match your cadence and gear, plug the values into the calculator to see whether a wheel-size setting is wrong.
- • Plan interval workouts in RPM zones: Lock in 90 RPM for sweet-spot intervals and 70 RPM for strength intervals, then read the speed each effort will produce.
These benefits compound when you use the calculator before rides, because a planned cadence is much easier to hold than one you discover mid-ride.
Cyclists who cross-train with running can pair the cadence work with the Running Pace and Race Split Calculator to compare effort across sports, since both calculators express pace in a way that lines up with heart-rate training zones.
Factors That Affect Your Bike Cadence Result
Five factors have the biggest effect on the number the calculator returns, and understanding them helps you decide when to trust the result and when to measure instead.
Wheel and tire geometry
The rim diameter plus twice the tire thickness sets the wheel circumference, and a 2 inch tire change moves the outside diameter by 4 percent, shifting the cadence reading by a few RPM at the same speed.
Drivetrain gear ratio
A switch from 50×17 to 50×19 drops the ratio from 2.94 to 2.63, which at the same speed lowers cadence by about 10 percent, the single biggest practical handle a cyclist has.
Actual rolling circumference
Inflated tire thickness varies with rider weight and pressure, and tire manufacturers rate sizes with a small tolerance, so measure a loaded bike for the most accurate result.
Speed measurement accuracy
GPS bike computers drift under tree cover and at low speeds, so a 5 percent speed error produces a 5 percent cadence error.
Pedal stroke smoothness
Cyclists with very smooth pedal strokes can hold a lower cadence at the same power, while riders with choppier strokes benefit from a higher RPM, so cadence targets are a starting point, not a rule.
- • The model assumes a fixed gear ratio, so a continuously variable transmission or an electronic shifting event mid-ride is not represented.
- • The calculator does not account for tire slip, braking, or climbing gradient, so on loose gravel or wet roads the actual speed will trail the calculated speed.
- • Wind, drafting, and elevation change the effort required at a given cadence but do not change the mechanical relationship this tool models.
According to Physiology of Cycling cadence guide, an 80 to 100 RPM pedaling cadence is typical for efficient road cycling, with about 70 RPM commonly used for endurance and recovery rides.
According to Wikipedia gear ratio reference, the bicycle gear ratio is the chainring tooth count divided by the rear cog tooth count, which determines how many wheel turns result from each pedal revolution.
Triathletes who need to hold a target cadence across the bike leg can feed the calculator's predicted speed into the Triathlon Finish Time Calculator to estimate the bike split and total race time.
Frequently Asked Questions
Q: How do you calculate bike cadence from speed?
A: Convert your speed to meters per minute, divide by the wheel circumference in meters, then divide by the gear ratio (chainring teeth divided by rear cog teeth). The result is pedal revolutions per minute, and the calculator does all three steps in real time.
Q: What is a good cadence for cycling?
A: Most road cyclists settle between 80 and 100 RPM for efficient cruising, while endurance and recovery rides often sit closer to 70 RPM. Mountain bikers climbing technical terrain commonly use 60 to 75 RPM to keep torque high.
Q: Does wheel size change bike cadence?
A: Yes. A larger outside diameter covers more distance per wheel revolution, so at the same speed and gear ratio a 29er wheel produces a lower cadence than a 26 inch wheel. Always enter the rim diameter plus twice the tire thickness for an accurate result.
Q: How does gear ratio affect bike cadence?
A: A higher gear ratio means the wheel turns more times per pedal revolution, so at a fixed speed the cadence drops. Shifting to a smaller cog or larger chainring is how cyclists lower cadence at the same speed without changing wheel size.
Q: What cadence should I aim for on a road bike?
A: For steady road riding, aim for 85 to 95 RPM once warmed up, dropping to 75 to 80 RPM for seated climbs and pushing 95 to 105 RPM for short sprints. The calculator labels the result so you can see which zone you are in.
Q: Is higher cadence better for endurance cycling?
A: A higher cadence recruits different muscle fibres and can reduce muscular fatigue on long rides, but it also costs more cardiovascular energy at the same speed. Most endurance coaches land on 80 to 90 RPM as the practical balance, and the calculator helps you stay in that window.