FTP Calculator

Functional threshold power (FTP) is the highest average power, in watts, that a cyclist can hold in a steady state for about one hour¹. A full hour test is hard to repeat, so most riders do a shorter test and multiply the result by a fixed factor. This calculator applies that factor, then splits your FTP into the seven Coggan power zones.

What FTP Measures

FTP is a single watts number that stands for the hardest pace you could keep up for roughly an hour. Coaches use it as the anchor for training zones. It is not your VO2 max or a heart rate, and it does not show calories burned. It is a field estimate, not a lab measurement.

The Formula

FTP from a 20-minute test = average power x 0.95

FTP from an 8-minute test = higher of two 8-minute average powers x 0.90

FTP from a ramp test = best 1-minute power x 0.75

Watts per kg = FTP in watts / body weight in kg

TrainingPeaks credits the 20-minute method to Hunter Allen and Andrew Coggan, and the 8-minute method to Chris Carmichael and Jim Rutberg². Zwift uses 75% of the best one-minute power during its ramp test³.

How This Calculator Computes Your Result

Pick a test, then enter the average watts from that test. For the ramp test, enter your best 1-minute average power from the whole test, including any part of the last step you finished. If you already know your FTP, choose that option and enter it directly. Body weight (kg or lb) and sex are optional. Weight is needed only for watts per kg, and sex is used only for the rating table below.

FTP is rounded to the nearest whole watt, and half a watt rounds up. Pounds are converted with 1 lb = 0.45359237 kg. Watts per kg is shown to two decimals. Your zones are built from the rounded FTP, and each zone starts 1 W above the top of the one before it, so there are no gaps.

What Your Result Means

Your result is your FTP in watts, watts per kg if you gave a weight, and seven power zones. The percentages below are Coggan's power training levels⁴ ⁵. The example column is for an FTP of 250 W.

The zone descriptions follow Coggan's TrainingPeaks article⁴. That article lists Zone 6 as "above 121%" and gives Zone 7 no percentage. Allen's TrainingPeaks article gives Zone 6 as 121 to 150% and Zone 7 as above 150%⁵, and this calculator uses those limits. Zone 7 is best judged by effort, not by a watts target.

What Your Watts Per Kilogram Means

Watts per kg compares riders of different sizes. The ratings below are Garmin's FTP ratings, which Garmin says are based on research by Hunter Allen and Andrew Coggan⁶. They are a rough guide, not a medical or racing standard.

How Well Does an FTP Estimate Match Your Real Threshold?

Reasonably well on average, less well for one person. In a study of 23 trained male cyclists, 95% of 20-minute power was close to the power from a 60-minute time trial on average. But for individual riders the gap between methods was wide. Across comparisons of 20-minute power, 60-minute power and a lab threshold, the limits of agreement ran from about 40 W below to 32 W above, up to 62 W below to 60 W above¹. The authors said the two should not be used interchangeably for one athlete¹.

Against lab markers, the picture depends on fitness. In 20 male cyclists, FTP averaged 240 W and the lactate threshold averaged 246 W, with a strong link (r = 0.95). In recreational riders, though, FTP read lower than the lactate threshold⁷. Another study of 18 well-trained adults (12 men and 6 women) found that power at the maximal lactate steady state was about 88.5% of 20-minute power, and about 93.1% of the 95% value. In 10 riders retested after 7 months of training, the lactate steady state improved but FTP did not change⁸.

Researchers also argue that critical power, not the lactate steady state, marks the true edge of steady-state exercise, and that the two measures are not interchangeable⁹. Put simply, FTP is a useful training number. It is not a precise physiological line.