FTP calculator
Enter the result of a 20-minute test or a ramp test. You get your FTP and the power zones that go with it, right away.
Your FTP
250W
95% of 263 W
| Zone | Power | % of FTP |
|---|---|---|
| Z1recovery | up to 137 Wup to 55% | up to 55% |
| Z2endurance | 138–187 W56–75% | 56–75% |
| Z3tempo | 188–225 W76–90% | 76–90% |
| Z4threshold | 226–262 W91–105% | 91–105% |
| Z5VO2 max | 263–300 W106–120% | 106–120% |
| Z6anaerobic | 301 W and upabove 120% | above 120% |
Watt4 keeps these numbers up to date from every ride and plans your week around them. Free. Try Watt4
What FTP is
FTP, functional threshold power, is the highest power you can hold for about an hour. It is the reference point for almost everything in training with power: your zones, your workouts and your training load are all set as a share of it.
A rider with an FTP of 250 W can hold roughly 250 W for an hour, flat out. Riding at 70% of FTP then means 175 W.
How the 20-minute test works
Warm up properly for 15 to 20 minutes, with a few short, hard efforts. Then ride 20 minutes as hard as you can hold evenly, and note the average power. Your FTP is 95% of that number: an average of 263 W gives an FTP of 250 W.
The 5% comes off because 20 minutes is shorter than an hour. Pace it evenly: going out too hard in the first five minutes is the usual way to get a low result.
How the ramp test works
A ramp test starts easy and adds power every minute, often about 20 W, until you can no longer hold the target. It is short and needs no pacing, which makes it popular on smart trainers and Zwift. Your FTP is 75% of your best one-minute power: 333 W gives an FTP of 250 W.
Riders with a strong sprint tend to score high on a ramp test, and riders built for long efforts tend to score low. If the zones feel wrong after a week, trust the feeling and retest with a 20-minute effort.
Using your zones
Each zone is a range of power, set as a share of FTP. Most of your riding belongs in zone 2. Intervals usually sit in zones 4 and 5. Retest every six to eight weeks, or when sessions start to feel clearly easier or harder than they should.
What each zone is for
- Z1 recovery
- Easy spinning for recovery rides and warm-ups. It should feel like almost nothing.
- Z2 endurance
- The base of your training. Long rides you could hold for hours while chatting.
- Z3 tempo
- Steady and purposeful. Sustainable for an hour or more, but you are working.
- Z4 threshold
- Around your FTP. Intervals of 8 to 20 minutes that raise the power you can sustain.
- Z5 VO2 max
- Hard efforts of 3 to 8 minutes that raise your aerobic ceiling.
- Z6 anaerobic
- Short, very hard efforts under two minutes, and sprints.
Questions
How accurate is a 20-minute FTP test?
Close enough to train with, for most riders. The 95% factor is an average: some riders hold more than that for an hour, some less. What matters most is testing the same way each time, so you can see the change.
Ramp test or 20-minute test: which should I do?
The 20-minute test asks more of you, but usually gives a truer number for long efforts. The ramp test is easier to do well, especially the first time. Pick one and stick with it, so your results compare.
How often should I test my FTP?
Every six to eight weeks is common. Testing more often mostly measures how rested you are.
Can I work out my FTP without a test?
Yes, from hard efforts in normal rides, or from heart rate over many steady rides. That is what Watt4 does: it reads your rides from Strava and keeps your FTP up to date without a dedicated test.