Power-to-Weight Calculator
On the flat, raw watts set your speed; on a climb you are fighting gravity, so watts per kilogram decide it. That is why the same 250 W moves a 60 kg rider up a hill far faster than an 85 kg one.
Your numbers
Watts per kg
3.47
Change
1.41%
What it means
2.5–4 W/kg is the committed club range; long climbs are where the gaps open.
Formula
Watts per kg = Power (W) ÷ Weight (kg)
The second figure shows what losing one kilogram does to the ratio. It is usually easier than adding the equivalent watts — but if muscle goes too, the power falls with it.
What to enter
| Input | Default | Accepted range |
|---|---|---|
| Power (W)Cycling power; use a sustained figure such as FTP. | 250 | 0 and up |
| Weight (kg) (kg)The second weight you are comparing against. | 72 | 0 and up |
Step by step
Quick reference table
Results when only Power (W) changes and everything else stays put.
| Power (W) | Watts per kg | Change (%) |
|---|---|---|
| 125 | 1.74 | 1.41 |
| 188 | 2.61 | 1.41 |
| 250 | 3.47 | 1.41 |
| 375 | 5.21 | 1.41 |
| 500 | 6.94 | 1.41 |
What each result means
| Result | At default values |
|---|---|
| Watts per kgPower over body weight — what decides climbing speed. | 3.47 |
| Change (%)How far it moved, measured against the before value. | 1.41 |
Common mistakes
The second figure shows what losing one kilogram does to the ratio. It is usually easier than adding the equivalent watts — but if muscle goes too, the power falls with it.
Glossary
- Power (W)
- Cycling power; use a sustained figure such as FTP.
- Weight (kg)
- The second weight you are comparing against.
- Watts per kg
- Power over body weight — what decides climbing speed.
- Change
- How far it moved, measured against the before value.
Frequently asked questions
Q. How is Power-to-Weight Calculator calculated?
Watts per kg = Power (W) ÷ Weight (kg) — On the flat, raw watts set your speed; on a climb you are fighting gravity, so watts per kilogram decide it. That is why the same 250 W moves a 60 kg rider up a hill far faster than an 85 kg one.
Q. Can you walk through an example?
With Power (W) 250, Weight (kg) 72kg, the answer is Watts per kg 3.47.
Q. What do I need to enter?
Enter Power (W), Weight (kg). The result recalculates as you type, and an empty box counts as zero.
Q. How much does the answer move if I change a number?
Changing only Power (W) moves the answer to Power (W) 125 → Watts per kg 1.74 and Power (W) 500 → Watts per kg 6.94. The table below lays out five steps.
Q. How are the numbers rounded?
Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.
Q. Anything to watch out for?
The second figure shows what losing one kilogram does to the ratio. It is usually easier than adding the equivalent watts — but if muscle goes too, the power falls with it.
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