Training / Cycling
Watts per kg Calculator: Cycling Power to Weight and FTP Classes
Divide your power, such as your functional threshold power, by your weight to get watts per kilogram, see the FTP class from Allen and Coggan's power tables for men or women, and how many watts each class needs at your weight.
Watts per kg Calculator: Cycling Power to Weight and FTP Classes: Power to weight is watts ÷ kilograms: 250 W at 75 kg is 3.33 W/kg. That FTP falls in the Good class for men, from 2.79 to 3.92 W/kg, and in Excellent for women, from 3.33 W/kg. The table gives the watts needed for each class at your weight: for this rider, 295 W for Excellent. Runs 100% locally in your browser with zero server file uploads.
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| Class | From (W/kg) | Power needed at your weight |
|---|---|---|
| Superior | 5.05 | 379 W |
| Excellent | 3.93 | 295 W |
| Good | 2.79 | 210 W |
| Fair | 2.23 | 168 W |
| Untrained | — | — |
Power to weight is your power in watts divided by your weight in kilograms; it decides how fast you climb, where weight matters most. The classes apply to functional threshold power, the power you can hold for about an hour, and follow Hunter Allen and Andrew Coggan's Training and Racing with a Power Meter (2010), in the bands Garmin publishes. Short efforts, such as a 5-minute or sprint power, give much higher numbers and need their own tables.
Where the classes come from
The bands follow Hunter Allen and Andrew Coggan's Training and Racing with a Power Meter (2010), as Garmin publishes them for its watches and bike computers. For men: Superior from 5.05 W/kg, Excellent 3.93, Good 2.79, Fair 2.23; for women: 4.30, 3.33, 2.36, and 1.90.
Improving the ratio
Raising power through structured training usually helps more than losing weight, and cutting weight too far costs power. Plan training intensity with the heart rate zone calculator.
How to use it
- Enter your power in watts, such as your FTP from a test or your bike computer.
- Enter your weight in kilograms or pounds and choose men's or women's classes.
- Read your W/kg, your class, and the watts needed for the next one.
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Frequently asked questions
What is FTP?
Functional threshold power: the highest average power you can hold for about an hour, usually estimated as 95% of a 20-minute all-out test.
Why does W/kg matter more than watts?
Climbing is mostly lifting your weight against gravity, so a lighter rider with less power can climb as fast; on the flat, air resistance matters more, and raw watts count more.
Should I include the bike's weight?
Not for comparing with the classes, which use body weight only. For working out a climbing speed, the bike and kit add to the weight being lifted.
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