Cycling FTP Calculator

FTP (Functional Threshold Power) is the cornerstone metric of structured cycling training. It is the highest average power output, measured in watts, that a rider can sustain for approximately one hour. All training zones, workout targets, and performance benchmarks are calculated as percentages of FTP, making it the single most important number in a cyclist’s training file.

FTP estimation formulas by test type:

FTP (20-min test) = Average Power over 20 minutes × 0.95

FTP (8-min test) = Average Power over 8 minutes × 0.90

FTP (Ramp test) = Peak 1-minute power of last completed step × 0.75

Power-to-Weight Ratio:

W/kg = FTP (watts) / Body Weight (kg)

Variable definitions:

• FTP: Functional Threshold Power; the power level at lactate threshold (where lactate production equals clearance)
• 0.95 factor: the 20-min test produces power slightly above true 1-hour threshold; the 5% reduction normalizes it
• W/kg: watts per kilogram; the truest measure of climbing ability and comparative performance across body sizes
• Training Zones: power ranges defined as percentages of FTP, each targeting a specific physiological adaptation

Worked example: A 75 kg cyclist averages 285 watts over a 20-minute FTP test. FTP = 285 × 0.95 = 270.75 watts → 271 watts W/kg = 271 / 75 = 3.61 W/kg, which is Cat 3 territory

Training zone targets based on FTP:

Zone 7 has no upper bound. It is a sprint zone measured in seconds, not a range you hold, so any figure quoted as its ceiling is invented.

W/kg performance benchmarks

These are Coggan’s racing-category classifications, and they are the same figures used by the training zones and power zones calculators on this site, so the three agree.

Women’s thresholds sit roughly 0.5 W/kg lower at every category, so a woman at 4.0 W/kg is racing at the level a man reaches around 4.5.

Retesting frequency: FTP changes with training. Retest every 6–8 weeks during active training blocks. FTP typically improves 5–15% over a well-structured 12-week training plan for recreational riders. Tour de France winners sustain 6.0–6.5 W/kg at threshold, a number most riders can only dream of.