FTP calculator (cycling)
Estimate your cycling Functional Threshold Power from a 20-minute test.
Related tools
All Running & endurance tools →Need FTP (W), Power-to-weight (W/kg)? The FTP calculator (cycling) derives it from Average 20-min power (W), Body weight (kg) in one step. For instance, with Average 20-min power (W) = 250 and Body weight (kg) = 70 it returns FTP (W) = 238 and Power-to-weight (W/kg) = 3.393.
How to use it
- Enter your values: Average 20-min power (W), Body weight (kg).
- Read the result instantly: FTP (W), Power-to-weight (W/kg).
Frequently asked questions
What does the FTP calculator (cycling) actually compute?
It takes Average 20-min power (W) and Body weight (kg) and derives FTP (W) and Power-to-weight (W/kg) from them. The calculation is live as you type, so the result updates on every change.
What information do I need to provide?
2 values: Average 20-min power (W) and Body weight (kg). Nothing else is required — no account, no file upload.
Can you show a worked example?
With Average 20-min power (W) = 250 and Body weight (kg) = 70, the calculator returns FTP (W) = 238 and Power-to-weight (W/kg) = 3.393. Those figures come from running this exact tool, so you can reproduce them by entering the same values.
What happens if I enter larger values?
It moves a lot. Using Average 20-min power (W) = 500 and Body weight (kg) = 77 instead, FTP (W) goes from 238 to 475 — which is why it is worth testing a few scenarios rather than trusting a single figure.
What does it give for smaller values?
Scaled down to Average 20-min power (W) = 125 and Body weight (kg) = 63, FTP (W) comes out at 119. The relationship is worth checking at both ends before you rely on a single result.
When would I actually use this?
Preparing a race: the pace a target time needs, the splits to hold it, and the training zones that sit under it — on foot, and equally on a bike or in a pool, where the same session is measured in watts or in a hundred-metre split instead.
What is the most common mistake?
Scaling a time linearly to a longer distance. A marathon is not two half-marathons; race predictors use an exponent around 1.06 precisely because fatigue is not proportional.
What is the difference between the FTP calculator (cycling) and the Cycling power calculator?
This one returns FTP (W) and Power-to-weight (W/kg); the Cycling power calculator returns Power. That is the whole difference — open the one whose figure you need.
Is there a tool for the next step?
Cycling Power Zones Calculator is the closest one after this: Get your Coggan cycling power zones (Z1–Z5) from your FTP.
What else is worth having open alongside it?
Cycling speed calculator and Running calories calculator — they come up in the same task often enough to be worth a second tab.