Cycling Power to Weight Calculator
Enter your functional threshold power (FTP) and your weight to get your watts per kilogram, and your Coggan power zones in watts. Add your bike weight to see the figure for rider plus bike, which is what matters on a climb. Use it to check your FTP watts per kg and the power zones that go with it.
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Formula
watts per kg = FTP (W) / rider weight (kg)watts per kg with bike = FTP (W) / (rider weight + bike weight) (kg)- Pounds are converted with
1 lb = 0.45359237 kg.
Coggan power zones
| Zone | Name | % of FTP |
|---|---|---|
| 1 | Active recovery | up to 55% |
| 2 | Endurance | 56 to 75% |
| 3 | Tempo | 76 to 90% |
| 4 | Threshold | 91 to 105% |
| 5 | VO2 max | 106 to 120% |
| 6 | Anaerobic capacity | 121 to 150% |
| 7 | Neuromuscular power | above 150% |
Zone limits in watts are rounded to the nearest whole watt.
Worked example
FTP 250 W, rider 70 kg, bike 8 kg:
- Rider only: 250 / 70 = 3.57 W/kg
- Rider plus bike: 250 / 78 = 3.21 W/kg
- Zone 2 (56 to 75%): 140 to 188 W; zone 4 (91 to 105%): 228 to 263 W; zone 7 starts at 378 W
When to use it
Watts per kilogram matters on climbs, where gravity is the main resistance. On flat roads total watts and aerodynamics matter more, so a heavier rider can be faster there with the same W/kg.
Typical values (rules of thumb)
- About 2.0 to 2.5 W/kg: recreational rider.
- About 3.0 to 3.5 W/kg: fit club rider.
- About 4.0 W/kg or more: strong amateur racer.
- 5.0 W/kg or more: elite or professional range.
These bands are informal.
Common mistakes
- Using a 20-minute test power without applying the usual 95% factor to estimate FTP.
How it differs from nearby tools
The cycling speed calculator turns gearing and cadence into speed. The cycling calories calculator turns average power into energy. This page only expresses your threshold power relative to weight.
Frequently asked questions
How do I calculate watts per kilogram?
Divide your power in watts by your body weight in kilograms. An FTP of 250 W at 70 kg is 250 / 70 = 3.57 W/kg. If you weigh yourself in pounds, divide by 2.2046 first (154 lb is 69.85 kg).
What are the Coggan power zones?
Andrew Coggan's seven zones are percentages of FTP: 1 active recovery up to 55%, 2 endurance 56-75%, 3 tempo 76-90%, 4 threshold 91-105%, 5 VO2 max 106-120%, 6 anaerobic capacity 121-150%, and 7 neuromuscular power above 150%. For an FTP of 250 W, zone 2 is 140-188 W.
Why include the bike weight?
On climbs you lift rider, bike, kit and bottles. With a 70 kg rider on an 8 kg bike, 250 W is 3.21 W/kg for the whole system, compared with 3.57 W/kg for the rider alone. Rider-only figures are the usual way to compare riders; the system figure is better for estimating climbing speed.
What is a good power to weight ratio?
It depends on age, sex and experience. Many recreational riders sit around 2 to 3 W/kg at FTP, committed club riders around 3.5 to 4.5, and professional climbers above 6. Treat these as rough bands, not targets.
How accurate are the zones?
The zones are a model built on your FTP, so they are only as good as that number. An FTP test gives an estimate that can shift by several percent between tests and with fatigue. Watt values are rounded to the nearest whole watt.
What is FTP and how is it estimated?
FTP (functional threshold power) is roughly the highest power you can hold for about an hour. A common estimate is 95% of your best 20 minute power, so a 316 W 20 minute test suggests an FTP near 300 W.
How much does losing 2 kg change watts per kg?
At 300 W FTP, a 75 kg rider has 300 / 75 = 4.00 W/kg. Dropping to 73 kg at the same power gives 300 / 73 = 4.11 W/kg, which is why weight loss helps on climbs.
What are the power zones for an FTP of 300 watts?
Using the Coggan percentages, zone 2 is 168 to 225 W, zone 4 (threshold) is 273 to 315 W and zone 7 starts above 453 W. Zone 1 is anything up to 165 W.