Bike Cadence to Speed Calculator

What is Bike Cadence?

Cadence in cycling refers to the number of revolutions your pedals make per minute (RPM). It's a fundamental metric that affects your efficiency, power output, and joint stress. Unlike speed, which varies with terrain and wind, cadence is purely about your pedaling rhythm.

Most cyclists fall into one of two camps: "spinners" who prefer high cadence (90-100+ RPM) with lighter gears, or "mashers" who push harder gears at lower cadence (60-75 RPM). Research consistently shows that higher cadences (85-100 RPM) are more efficient for most riders and reduce knee strain.

How to Calculate Speed from Cadence

The formula combines your pedaling rate with your bike's mechanical advantage: Speed = (Cadence × Gear Ratio × Wheel Circumference).

What is a Good Cycling Cadence?

Optimal cadence varies by rider fitness, terrain, and discipline, but general guidelines exist:

• 85-100 RPM (Optimal for Most): This range is considered the sweet spot for efficiency on flat to rolling terrain. It balances muscle fatigue and cardiovascular load, making it sustainable for long rides.
• 60-80 RPM (Climbing/Power Riding): On steep climbs or during sprints, cadence naturally drops as you apply more force. Time trialists may also use lower cadences to maximize power output over short durations.
• 100-120 RPM (Professional Racing): Elite road racers often spin at very high cadences to preserve leg freshness over multi-hour events. Track cyclists may exceed 130 RPM during attacks.
• Below 60 RPM (Inefficient): Consistently pedaling below 60 RPM ("grinding") puts excessive stress on knees and tendons. It's fine for brief power efforts but should be avoided during endurance riding.

Why Higher Cadence is Generally Better

Pedaling at 90+ RPM reduces the peak force on each pedal stroke, distributing effort over more repetitions. This lowers muscle fatigue and joint stress, particularly on the knees and Achilles tendons. Studies show that recreational cyclists who increase cadence from 70 to 90 RPM often report less knee pain and improved endurance.

Limitations of Cadence-to-Speed Conversion

While this calculator provides an accurate theoretical speed, real-world riding involves additional variables:

• Wind Resistance: Headwinds dramatically reduce speed at the same power output. At 20 mph, roughly 80% of your energy fights air resistance.
• Terrain: Climbing reduces speed even if cadence and gearing remain constant. Gradient, not gear ratio alone, determines uphill speed.
• Tire Pressure & Rolling Resistance: Under-inflated tires or rough surfaces increase rolling resistance, slowing you down without changing cadence.
• Drivetrain Efficiency: A clean, well-lubricated chain is 98-99% efficient, while a dirty drivetrain can lose 3-5 watts, slightly reducing actual speed.

For a more comprehensive analysis of cycling performance, consider using a power meter to measure watts output, which accounts for all these variables.