Convert your pedal cadence (RPM) to speed based on wheel size and gear ratio
This tool helps cyclists understand the relationship between pedal cadence (how fast you pedal), gear selection, wheel size, and resulting speed. Here's how to use it:
This is your actual speed based on your cadence and current gear selection. The calculation accounts for your wheel circumference and gear ratio to provide an accurate speed estimate.
The gear ratio is calculated by dividing the number of teeth on your front chainring by the number of teeth on your rear cog. A higher ratio means you'll go faster at the same cadence but requires more effort. A lower ratio is easier to pedal but results in lower speed.
This shows how far forward your bike travels with each complete rotation of the pedals. This measurement is useful for understanding mechanical advantage and planning gear changes for different terrain.
Different types of cycling benefit from different cadence ranges:
Most cycling coaches recommend training at 85-95 RPM for optimal cardiovascular efficiency and reduced muscle fatigue.
The speed calculation uses the following formula:
Where:
Wheel circumference varies based on tire size and inflation pressure. Common sizes include:
Most cyclists perform best at 80-100 RPM. Beginners often pedal at 60-70 RPM, while experienced road cyclists typically maintain 90-100 RPM. Higher cadences reduce muscular strain and improve cardiovascular efficiency.
You can use a cycling computer with a cadence sensor, a smartphone app with your phone mounted to your bike, or count pedal revolutions for 15 seconds and multiply by 4.
Yes, slightly. Higher tire pressure results in a slightly larger effective wheel diameter. The difference is typically 5-15mm in circumference, which translates to less than 1% speed variation at most cadences.
GPS speed accounts for actual ground speed including factors like wind resistance, road gradient, tire slip, and rolling resistance. This calculator provides theoretical speed based on mechanical rotation only.
For climbing, use lower gear ratios (1.0-2.0) which allow you to maintain a comfortable cadence (70-90 RPM) while ascending. For flat terrain or descents, higher ratios (2.5-4.0+) are more efficient.
Yes, if your indoor bike has adjustable resistance that simulates gear changes. Many smart trainers and spin bikes display cadence, and this tool can help you understand what speed that cadence would produce outdoors.