Watts Per Kg Calculator
Calculate your power-to-weight ratio to determine your climbing ability and racing category.
What is Watts/kg?
Watts per kilogram (W/kg) is the most critical metric for climbing performance. Since gravity is the primary resistance when going uphill, a lighter rider needs fewer watts to go the same speed as a heavier rider. W/kg normalizes power output by body weight, allowing for a direct comparison of climbing potential.
How to use this number
- Zwift Racing: Categories are primarily based on your FTP W/kg. (Cat A: 4.0+, Cat B: 3.2-3.9, Cat C: 2.5-3.1, Cat D: <2.5).
- Climbing Benchmarks: To ride with the pros in the mountains, you typically need to sustain 5.5-6.0 W/kg for 20-60 minutes.
- Training Goals: Tracking improvements in W/kg is often more useful than tracking raw watts, especially if your weight fluctuates.