Cycling Watts per Kg Calculator

This calculator works out a cyclist’s power-to-weight ratio. Enter the power in watts (for example your functional threshold power) and your body mass in kilograms; you get watts per kilogram and watts per pound.

Formula

W/kg = power ÷ mass in kg. W/lb = power ÷ (mass × 2.2046).

Worked Example

250 W and 72 kg.

1. W/kg = 250 ÷ 72 = 3.47
2. W/lb = 250 ÷ (72 × 2.2046) = 250 ÷ 158.73 = 1.57

How to read the result

Watts per kilogram decides climbing speed, because on a steep hill you lift your own mass. On flat roads absolute watts and aerodynamics matter more. Compare like with like: a 5-minute power gives a higher figure than a one-hour threshold power.

Limits and common mistakes

• Some riders include the bike mass; this page uses body mass only.
• Power meters differ by a few percent.

Frequently Asked Questions

What is a good FTP in W/kg?

Many recreational riders are around 2.5-3.5 W/kg; elite pros are above 5.5.

Should I include bike weight?

Not for the usual W/kg figure; include it for climbing-speed estimates.

How do I raise W/kg?

Raise power, lower mass, or both.

How do I convert W/kg to W/lb?

Divide by 2.2046.

in p | Power | W | 250 | 0 | 3000
in kg | Body mass | kg | 72 | 20 | 300
out wkg | Power to weight | W/kg | p / kg | 2
out wlb | Power to weight | W/lb | p / (kg * 2.2046226218) | 2