Power-to-Weight Calculator
Work out your power-to-weight ratio in watts per kilogram (W/kg) from a power figure and your body mass, and — if you enter your FTP — your FTP-relative W/kg alongside it.
Reference bands: Allen & Coggan power profile • Checked 24 Aug 2026Enter your numbers
How power-to-weight is calculated
Power-to-weight ratio is simply how much power you produce for each kilogram of body mass. On a climb, gravity scales with your mass, so two riders holding the same watts move at very different speeds if they weigh differently — which is why cyclists, rowers and other endurance athletes quote W/kg rather than raw watts.
- power_watts
- the power output you are rating, in watts
- FTP_watts
- functional threshold power — roughly the highest power you can hold for about an hour
- body_mass_kg
- your body mass in kilograms (1 lb = 0.45359237 kg)
Both are plain ratios — divide watts by kilograms. The only subtlety is the duration the power figure represents: a 5-second sprint W/kg and an FTP W/kg describe very different efforts and are not comparable.
Worked example: 250 W at 70 kg
- Power-to-weight:
250 / 70 = 3.57 W/kg - With an FTP of 260 W:
260 / 70 = 3.71 W/kg - The same rider in pounds:
154 lb × 0.45359237 = 69.85 kg, so250 / 69.85 = 3.58 W/kg
An FTP of about 3.7 W/kg sits in the trained-to-competitive club range in the guide below.
Approximate FTP W/kg tiers
The bands below are a rough, illustrative guide to where FTP-relative W/kg tends to fall, based on the power-profiling concept popularised by Allen & Coggan. They are approximate only and simplified to a handful of rows — the full published power-profile chart is copyrighted and broken down by effort duration and sex, so we do not reproduce it here. Men’s and women’s tiers differ; see the source for the complete tables.
| Approx. FTP W/kg | Indicative level |
|---|---|
| ~2 W/kg | Recreational |
| ~3 W/kg | Trained / enthusiast |
| ~4 W/kg | Competitive club racer |
| ~5+ W/kg | Elite / professional |
These figures are for a nominal 20-minute or FTP effort. For the full duration-by-sex tables, see Allen & Coggan, Training and Racing with a Power Meter.
Accuracy notes and limits
Watts per kilogram is just power divided by mass — it tells you nothing on its own about the duration or protocol behind the power figure. A sprint W/kg, a 5-minute W/kg and an FTP W/kg are all different numbers for the same rider. The tier bands above depend on effort duration, sex and how FTP was tested, so treat them as indicative only. This is an educational reference, not coaching advice.
Frequently asked questions
Do I need to enter my FTP?
No. Enter any power figure to get its W/kg. Adding your FTP simply shows a second, FTP-relative W/kg — the number most cycling tier tables are built around.
Why convert pounds to kilograms?
W/kg is defined per kilogram, so pounds are converted using 1 lb = 0.45359237 kg before dividing. The power figure is always in watts.
Are the tiers the same for men and women?
No. Men’s and women’s power-profile bands differ, and they also vary by effort duration. The rows here are a simplified guide — see Allen & Coggan for the full tables.
Related tools and reading
Understanding power-to-weight ratio
What W/kg means for climbing, why duration matters and how to read the power profile.
Sources
- Allen, H. & Coggan, A. Training and Racing with a Power Meter. VeloPress — power profiling and FTP W/kg tables.