Calculate watts per kilo (W/kg) from power in watts and body weight in kg or lb, or work back to the power or weight for a target W/kg.
Watts Per Kilo Formula
The main watts per kilo formula is:
The calculator can also rearrange the formula to solve for watts or total weight:
When needed, the calculator converts units before applying the formula:
- WPK = watts per kilo, measured in W/kg
- W = power output in watts
- M = total weight or mass in kilograms
- kW = kilowatts
- lb = pounds
If you enter watts and total weight, the calculator finds watts per kilo by dividing watts by weight in kilograms.
If you enter total weight and watts per kilo, it finds the required watts by multiplying weight by watts per kilo.
If you enter watts and watts per kilo, it finds total weight by dividing watts by watts per kilo.
Watts Per Kilo Conversion Reference
Use these values to check how the calculator handles unit conversions.
| Conversion | Formula | Example |
|---|---|---|
| Kilowatts to watts | W = kW × 1000 | 0.25 kW = 250 W |
| Pounds to kilograms | kg = lb × 0.45359237 | 154 lb ≈ 69.8532 kg |
| W/lb to W/kg | W/kg = W/lb ÷ 0.45359237 | 2 W/lb ≈ 4.4092 W/kg |
| W/kg to W/lb | W/lb = W/kg × 0.45359237 | 4 W/kg ≈ 1.8144 W/lb |
Watts per kilo compares power output to mass. The following ranges are arithmetic examples, not fitness standards. Compare the same effort duration and mass basis; a short sprint and a sustained effort are not interchangeable.
| Watts per kilo | Illustrative power at 70 kg |
|---|---|
| Below 2.0 W/kg | Below 140 W |
| 2.0 to 3.0 W/kg | 140 to 210 W |
| 3.0 to 4.0 W/kg | 210 to 280 W |
| 4.0 to 5.0 W/kg | 280 to 350 W |
| Above 5.0 W/kg | Above 350 W |
Example Watts Per Kilo Calculations
Example 1: Calculate watts per kilo
You weigh 70 kg and produce 280 W.
Your result is 4.0000 W/kg.
Example 2: Calculate required watts
You weigh 165 lb and want to reach 3.5 W/kg.
First convert pounds to kilograms:
Then multiply by watts per kilo:
The required power is about 261.9496 W.
Watts Per Kilo Calculator FAQ
What does watts per kilo mean?
Watts per kilo means watts of power for each kilogram of total weight. A value of 4 W/kg means you produce 4 watts for every kilogram of weight. If total weight is 70 kg, 4 W/kg equals 280 W.
Should total weight include bike and gear?
It depends on what you are measuring. For body-only fitness comparisons, use body weight. For real climbing performance on a bike, use total system weight, including rider, bike, bottles, clothing, and gear.
Why can two people with the same watts have different watts per kilo?
Watts per kilo depends on both power and weight. If two people both produce 250 W, the lighter person has a higher W/kg value because the same power is divided by a smaller weight.
