What is a good watts per kilogram figure?

A recreational rider sits around 2.0-3.0 W/kg, a strong amateur racer is 3.5-4.5 W/kg, and elite pros sustain 5.5-6.5 W/kg at threshold. Higher W/kg means you climb and accelerate faster relative to your size.

Should I use 20-minute power or FTP?

Use your FTP (functional threshold power). FTP is typically estimated as 95% of your best 20-minute average power, so apply that discount before entering the figure for an accurate threshold W/kg.

Why does W/kg matter more than raw watts on climbs?

On a climb you must lift your whole body mass against gravity, so the deciding factor is power relative to weight. On flat ground aerodynamics and raw watts matter more, which is why heavier riders can still be fast on the flat.

How do I improve my W/kg?

You can raise the numerator by training to increase FTP, or lower the denominator by safely reducing excess bodyweight. Most riders gain the most by combining structured threshold training with sensible body composition work.

Are these the same bands Zwift uses?

The bands here mirror the widely used Zwift and TrainerRoad category guidance (A/B/C/D). Zwift racing categories can shift slightly over time, so treat the result as a close guide rather than an official ranking.

Cycling Watts Per Kilogram Calculator

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Power-to-weight in one number

Cyclists are ranked by watts per kilogram (W/kg) — your sustainable power divided by your bodyweight. It is the single most useful number for predicting climbing performance, because on a gradient you are working against gravity acting on your total mass. This calculator takes your FTP and weight and returns your threshold W/kg plus the category band you fall into.

How it works

The formula is simply:

W/kg = FTP (watts) / bodyweight (kg)

If you enter weight in pounds it is converted with 1 kg = 2.20462 lb before dividing. The result is mapped onto commonly used threshold-power category bands:

Under 2.0 — Cat D, untrained / new rider
2.0 to 3.1 — Cat C, recreational
3.1 to 4.0 — Cat B, club racer
4.0 to 5.0 — Cat A, strong amateur
5.0 and above — elite / professional

These thresholds match the guidance popularised by Zwift and TrainerRoad for sorting riders by ability.

Example and tips

A 75 kg rider with an FTP of 280 W has 280 / 75 = 3.73 W/kg, placing them in Cat B. To climb with the Cat A group they would need roughly 300 W at the same weight, or the same 280 W at about 70 kg. Always test your FTP on the same kind of effort (ramp or 20-minute) so comparisons over a season stay consistent, and re-measure every 6-8 weeks of training.