Functional threshold power (FTP) is the highest power you can hold for about an hour. Power zones based on it tell you exactly how hard each workout should be – far more precisely than heart rate.
How to use the Cycling Power Zones Calculator
- I know
- Power (W)
- Body weight
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Choose how you know your FTP, enter the power, and your weight for W/kg.
Tips
- Practise transitions – they count towards your total time.
- Train your race-day nutrition as carefully as your fitness.
- Heart rate zones differ slightly between swimming, cycling and running.
- Everything is calculated in your browser.
Common mistakes to avoid
- Going too hard on the bike and suffering on the run.
- Trying new food or gear on race day.
- Ignoring open-water skills.
Inputs explained
| Field | What to enter |
|---|---|
| I know | Choose one: My FTP, My 20-minute test average power, My best 1-minute power in a ramp test |
| Power (W) | A number |
| Body weight | Units: kg, lb |
What each result means
- FTP per kg = [Functional threshold power (FTP)]÷[Body weight]
- Z1 Active recovery: up to = round(0.55×[Functional threshold power (FTP)])
- Z2 Endurance: from = round(0.56×[Functional threshold power (FTP)])
- up to = round(0.75×[Functional threshold power (FTP)])
- Z3 Tempo: from = round(0.76×[Functional threshold power (FTP)])
- up to = round(0.90×[Functional threshold power (FTP)])
- Z4 Lactate threshold: from = round(0.91×[Functional threshold power (FTP)])
- up to = round(1.05×[Functional threshold power (FTP)])
- Z5 VO₂ max: from = round(1.06×[Functional threshold power (FTP)])
- up to = round(1.20×[Functional threshold power (FTP)])
- Z6 Anaerobic capacity: from = round(1.21×[Functional threshold power (FTP)])
- up to = round(1.50×[Functional threshold power (FTP)])
- Z7 Neuromuscular: above = round(1.50×[Functional threshold power (FTP)])
Example values
How the main result changes when Power changes and everything else stays at the example values above:
| Power (W) | Functional threshold power (FTP) (W) |
|---|---|
| 125 | 125 |
| 187.5 | 188 |
| 250 | 250 |
| 312.5 | 313 |
| 375 | 375 |
| 500 | 500 |
Formula
FTP = 0.95 × 20-min power, or 0.75 × best 1-min ramp-test power · Zones (% FTP): Z1 < 55 · Z2 56–75 · Z3 76–90 · Z4 91–105 · Z5 106–120 · Z6 121–150 · Z7 > 150
Worked example
Inputs — I know: My FTP; Power (W): 250; Body weight: 72 kg.
Results — Functional threshold power (FTP) = 250 W; FTP per kg = 3.47 W/kg; Z1 Active recovery: up to = 138 W; Z2 Endurance: from = 140 W; up to = 188 W; Z3 Tempo: from = 190 W; up to = 225 W; Z4 Lactate threshold: from = 228 W; up to = 263 W; Z5 VO₂ max: from = 265 W; up to = 300 W; Z6 Anaerobic capacity: from = 303 W; up to = 375 W; Z7 Neuromuscular: above = 375 W.
Key terms
- FTP
- Functional threshold power – about 1-hour maximum power.
Frequently asked questions
What is a good FTP?
2.5–3.5 W/kg for fit amateurs; 5–6 W/kg for pros.
How do I test FTP?
Ride an all-out 20 minutes after a warm-up and take 95% of the average.
How often should I retest?
Every 6–8 weeks.
Why use W/kg?
It decides climbing speed and lets riders of different sizes compare.