How this instrument works
Functional Threshold Power, or FTP, is the highest power output a rider can sustain in a steady effort for roughly an hour. Andrew Coggan's widely used seven-zone model, published with Hunter Allen in Training and Racing with a Power Meter, defines every training zone as a percentage band of FTP, so once FTP is known, every zone boundary follows directly from simple multiplication.
Power-based zones respond to effort instantly, unlike heart rate, which lags behind sudden changes in pedalling force by tens of seconds. That immediacy is why power zones are generally preferred for interval-precision training, such as short, hard efforts where heart rate wouldn't catch up until the interval was already over — this site's cycling-hr instrument covers the heart-rate-based alternative for effort that unfolds more gradually.
FTP itself is usually established with a dedicated test — a common protocol is a 20-minute all-out effort, with FTP estimated as 95% of the average power held for those 20 minutes, though ramp tests and other protocols are also widely used. Because FTP shifts as fitness changes, most riders retest every few months through a training block to keep their zones accurate.
- Enter Functional Threshold Power, FTP (watts) — from a recent FTP test; 250 W is shown as a working reference point.
- Read Zone 1 through Zone 6 — each is the upper wattage boundary of that zone, from Active Recovery up to Anaerobic Capacity.
- Ride below Zone 1's figure for genuine recovery days, and between consecutive zone boundaries for the training effect each zone targets.
- FTP must be greater than zero, or the instrument will prompt for a valid value.
- Zone 7 (Neuromuscular Power) has no upper wattage boundary by definition, so it isn't computed here — anything above the Zone 6 figure falls into it.
Worked example — a 250 W FTP
Enter 250 into Functional Threshold Power, FTP (watts) — a solid, well-trained recreational rider's threshold power. Zone 1 reads 137.5 W, Zone 2 reads 187.5 W, Zone 3 reads 225.0 W, Zone 4 reads 262.5 W, Zone 5 reads 300.0 W, and Zone 6 reads 375.0 W.
That rider would ride under 137.5 W for genuine active recovery, hold roughly 187.5-225 W for a long steady endurance base ride, and push into the 262.5-300 W range for threshold intervals close to their hour-long limit. Anything above 375 W tips into short, very hard anaerobic efforts — sprints and short surges rather than sustained riding.
Questions
What is FTP and how do I test it?
FTP is the highest power a rider can sustain in a steady, roughly hour-long effort. A common way to estimate it is a 20-minute all-out time-trial effort, taking 95% of the average power held over those 20 minutes as FTP; ramp tests and other structured protocols are also widely used and can give slightly different results, so it's worth being consistent about which test method you use over time.
Why does Zone 6 have an upper bound here but Zone 7 doesn't?
Coggan's model defines Zone 6, Anaerobic Capacity, as roughly 121-150% of FTP, giving it both a lower and upper wattage boundary, which is what this instrument calculates. Zone 7, Neuromuscular Power, covers very short maximal sprints with no meaningful upper limit tied to FTP, so it's conventionally left open-ended rather than expressed as a percentage band.
How is this different from the cycling-hr instrument on this site?
This page calculates power-based zones in watts from FTP; cycling-hr instead calculates a heart-rate target in bpm from maximum heart rate, resting heart rate and a chosen intensity using the Karvonen method. Power responds instantly to effort while heart rate lags behind it by tens of seconds, so many structured training plans reference both together rather than relying on just one metric.
How often should I retest FTP and update these zones?
Most riders retest every four to eight weeks during a focused training block, since FTP shifts as fitness improves or declines, and zones calculated from a stale FTP figure will understate or overstate the actual effort a given wattage represents. A noticeable jump in how a previously hard zone feels is often a practical sign it's time to retest.
Where does this seven-zone percentage model come from?
It was developed by exercise physiologist Andrew Coggan and popularised together with Hunter Allen in their book Training and Racing with a Power Meter, first published in 2006 and now in multiple editions. It remains one of the most widely referenced power-zone frameworks in cycling coaching, alongside other systems that divide the same underlying power range slightly differently.