Power-to-Weight Ratio Calculator
Watts per kilogram, and what it means on a climb.
Roughly 95% of your best 20-minute average power.
Power-to-weight ratio
3.57 W/kg
Trained amateur
This ratio dominates on climbs, where you are lifting your own mass. On flat ground raw watts matter more, because the enemy is air resistance rather than gravity.
Rider categories at FTP
| Category | W/kg |
|---|---|
| Untrained | Below 2.5 |
| Recreational | 2.5 – 3.5 |
| Trained amateurYou | 3.5 – 4.5 |
| Competitive | 4.5 – 5.5 |
| Professional | 5.5 and above |
How the Power-to-Weight Ratio Calculator works
On flat ground, raw watts move a bike. On a climb, watts per kilogram decide almost everything — you are lifting your own mass against gravity. It is the single most-used number in cycling for exactly that reason.
Not medical advice. This calculator gives a general estimate, not medical advice. It cannot account for your individual health, medical history, or medication. Talk to a qualified healthcare professional before acting on any result.
Frequently asked questions
What is a good watts per kg?
At functional threshold power, roughly: 2.0-2.5 W/kg untrained, 3.0-3.5 recreational, 4.0-4.5 competitive amateur, and 5.5-6.5 for professionals. Grand-tour climbers sustain around 6 W/kg for extended climbs.
What is FTP?
Functional threshold power — roughly the highest average power you can hold for an hour. It is usually estimated as 95% of a 20-minute maximal effort, since a genuine one-hour test is brutal and rarely repeated willingly.
Should I lose weight or gain power?
Both raise the ratio, but they are not equally cheap. For a well-trained rider near optimal body composition, further weight loss costs power and often health. For most amateurs, gaining power is the larger and safer opportunity.
Why does power-to-weight matter less on flat ground?
Because on the flat you are fighting air resistance, which scales with frontal area and speed rather than mass. A heavier, more powerful rider is usually faster on flat terrain and slower uphill — which is why time trialists and climbers have different builds.