Free Cycling Power Zone Calculator (FTP Zones)
Enter your FTP to see your six power zones in watts — free, with no signup or subscription. The zones match the ones SurgeIQ Lab uses in the app.
Published
Your zones appear here. The scale below shows the zone boundaries as a percentage of FTP.
How to use the result
Each zone is a band of effort with a typical training purpose. Structured workouts usually give targets as a percentage of FTP; this table turns them into the watts you will see on your power meter.
| Zone | Typical use |
|---|---|
| Z1 Recovery | Very easy spinning: recovery rides, and the easy half of interval sessions. |
| Z2 Endurance | Long steady riding; the bulk of most endurance training time. |
| Z3 Tempo | Sustained, moderately hard efforts; the upper part is often called "sweet spot". |
| Z4 Threshold | Efforts around FTP, typically in blocks of about 8–20 minutes. |
| Z5 VO2max | Hard intervals of roughly 3–8 minutes with similar recovery. |
| Z6 Anaerobic | Short, very hard efforts of seconds to about two minutes. |
Example
With an FTP of 250 W, the work intervals of “4 × 5 min at 105–110% FTP” are 263–275 W — the bottom of Z5 — and the 3 min recoveries at 50–60% are 125–150 W.
- Warmup10 min50–65% FTP (125–163 W)
- Repeat 4×
- Work5 min105–110% FTP (263–275 W)
- Recover3 min50–60% FTP (125–150 W)
- Cooldown10 min<60% FTP (<150 W)
Limitations
- Zones are only as good as the FTP estimate; a 5% error shifts every boundary by 5%.
- Boundaries are conventions — neighbouring values either side of a boundary are not different efforts.
- Very short efforts depend on more than FTP, so Z6 targets are a rough guide.
- Heat, fatigue and altitude change how a given wattage feels.
Methodology
Boundaries are 55, 75, 90, 105, 120 and 150% of FTP, following Allen and Coggan’s power levels (Training and Racing with a Power Meter) as implemented in SurgeIQ Lab. The app shows six zones and does not display a separate neuromuscular level. Watts are rounded to the nearest whole number.