FTP Calculator
Functional threshold power from a 20-minute test (95%), plus W/kg.
Result
FTP (W)
238
FTP per kg (W/kg)
3.39
How it works
Your Functional Threshold Power (FTP) is the highest average power, in watts, that you can sustain for about an hour on the bike. It is the anchor of modern cycling training: once you know it, every workout intensity can be prescribed as a percentage of it. The standard field test is 20 minutes long: ride as hard as you can sustain evenly, take your average power, and multiply by 0.95 — the small discount converts a 20-minute effort into an estimated one-hour power. This calculator applies exactly that method. Training zones then follow: easy endurance rides sit around 56–75% of FTP, tempo 76–90%, threshold work 91–105%, and VO2max intervals 106–120%. Re-test every 6–8 weeks — a rising FTP is the clearest sign your fitness is improving.
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Frequently asked questions
Why 95%?
A full hour at threshold is brutal to test, so 95% of a 20-minute effort approximates it well.
How do I use FTP?
To set power-based training zones and pace longer efforts.
How often should I test my FTP?
Every 6 to 8 weeks during structured training. Testing more often adds fatigue without new information; less often lets your zones drift out of date.
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