Watts per KG Calculator
Work out your cycling power-to-weight ratio from your FTP (or a 20-minute, 8-minute or ramp test) and body weight, see where it sits on a power profile chart from untrained to world class, and how many watts you need for the next level.
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How to use the Watts per KG Calculator
- Enter your power in watts.
- Choose what the number is: FTP, or the average from a 20-minute or 8-minute test, or your best minute in a ramp test.
- Enter your body weight in kg or lb.
- Choose men's or women's chart to compare with.
- Read your W/kg and level, then see the watts needed for each level in the table.
FTP power-to-weight levels
Simplified ranges based on the FTP column of Andrew Coggan's power profile chart. Racing category labels are approximate.
| Level | Men (W/kg) | Women (W/kg) |
|---|---|---|
| World class (international pro) | 5.6 – 6.4+ | 4.9 – 5.7+ |
| Exceptional (domestic pro) | 5.1 – 5.6 | 4.4 – 4.9 |
| Excellent (Cat 1) | 4.6 – 5.1 | 3.9 – 4.4 |
| Very good (Cat 2) | 4.0 – 4.6 | 3.4 – 3.9 |
| Good (Cat 3) | 3.5 – 4.0 | 2.9 – 3.4 |
| Moderate (Cat 4) | 2.9 – 3.5 | 2.4 – 2.9 |
| Fair (Cat 5) | 2.4 – 2.9 | 2.0 – 2.4 |
| Novice | 1.9 – 2.4 | 1.5 – 2.0 |
| Untrained | < 1.9 | < 1.5 |
Formulas used
| Quantity | Formula | Example |
|---|---|---|
| Power-to-weight | W/kg = FTP ÷ mass (kg) | 250 W ÷ 75 kg = 3.33 |
| FTP from 20-min test | FTP ≈ 0.95 × 20-min average | 280 W → 266 W |
| FTP from 8-min test | FTP ≈ 0.90 × 8-min average | 320 W → 288 W |
| FTP from ramp test | FTP ≈ 0.75 × best 1-min power | 360 W → 270 W |
| Watts for a target | W = target W/kg × mass | 4.0 × 75 = 300 W |
The climbing estimate solves the cycling power equation (gravity, rolling resistance with Crr 0.005 and air drag with CdA 0.4 m²) for an 8% climb with an 8 kg bike. Real speeds vary with position, tyres, wind and pacing.
Frequently asked questions
How do you calculate watts per kg?
Divide your power in watts by your body weight in kilograms. A rider with an FTP of 250 W who weighs 75 kg has 250 ÷ 75 = 3.33 W/kg. If you weigh yourself in pounds, divide by 2.2046 first.
What is a good W/kg for cycling?
For FTP, around 2 to 2.5 W/kg is typical for newer riders, 3 to 4 W/kg is strong for amateur racers, over 4 W/kg is a high-level amateur or elite, and professional men often sustain 5.5 to 6.4 W/kg. Women's values are roughly 0.5 to 0.7 W/kg lower at each level.
What is FTP?
Functional threshold power is the highest average power you can sustain for about an hour. It is commonly estimated as 95% of your best 20-minute average power, 90% of an 8-minute test, or about 75% of the best one-minute power in a ramp test.
Where do the cycling categories come from?
The levels follow the FTP column of Andrew Coggan's power profile chart (from Training and Racing with a Power Meter), simplified into ranges. The Cat 1 to Cat 5 labels are approximate equivalents of USA Cycling racing categories, not official thresholds.
Why does W/kg matter more than watts?
On climbs, most of your power goes into lifting your body and bike against gravity, so speed uphill depends mainly on power per kilogram. On flat roads, absolute watts and aerodynamics matter more, which is why heavier, powerful riders can be fast on the flat.
Is it better to gain power or lose weight?
Both raise W/kg. The results show how many extra watts or how many kilograms less would reach the next level. Losing weight only helps if power stays the same, so for most riders structured training to raise FTP is the safer path.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.