Free Tool

W/KG CALCULATOR

Calculate FTP watts per kilogram, then interpret the result in context.

FTP (WATTS)

WEIGHT (KG)

METHODOLOGY

Formula: W/kg = FTP (watts) ÷ Body weight (kg). This tool does not estimate FTP. Enter a current value from a disclosed, repeatable method and keep that method attached to the result.

Reference ranges: The highlighted half-watt range is arithmetic context only. It is not a population percentile, age adjustment, race licence or professional classification. Use the maintained age and experience benchmark reports for qualified comparisons.

Limitations: FTP W/kg is one duration-specific ratio. Gradient, total rider-plus-bike mass, aerodynamics, wind, rolling resistance, drafting and pacing affect speed. Body mass also varies with hydration, food and measurement timing.

Last reviewed: 26 August 2026 · Tool version 1.1

Quick answer

Enter FTP in watts and body mass in kilograms. The calculator returns FTP W/kg and highlights the surrounding half-watt range. The arithmetic is exact; the range is context, not a race category, percentile or diagnosis of ability. Keep the test method and date attached to the result.

WHAT IT DOES

This calculator performs one disclosed operation: FTP watts divided by rider body mass in kilograms. It then locates the result inside a broad half-watt reference range without converting that range into a race licence or professional label.

FTP W/kg is useful for threshold-related climbing context. It does not describe sprint power, five-minute power, durability, aerodynamics, handling or race craft, and it does not predict speed independently of gradient, total system mass, wind, rolling resistance and pacing.

WHO IT'S FOR

→Cyclists who already have a current FTP estimate and want the ratio calculated
→Riders tracking a repeatable FTP W/kg baseline over time
→Masters cyclists who need a route from raw W/kg to a qualified age benchmark
→Coaches and self-coached riders explaining why one ratio is not a complete power profile

HOW IT WORKS

W/kg = FTP in watts ÷ rider body mass in kilograms. The tool does not estimate FTP or reconcile different protocols. Use a current value from a disclosed, repeatable method and a representative body-mass measurement. Record the device, protocol and date because a ramp estimate, 20-minute estimate, modelled FTP and long steady effort can disagree.

01
Choose a current FTP estimate
Use a value from a disclosed, repeatable power test or model. Keep the device and protocol beside the result rather than treating unlike FTP methods as interchangeable.
02
Use representative body mass
Enter kilograms from a consistent measurement routine. If tracking change, compare similar conditions because hydration and food can move body mass without changing fitness.
03
Calculate the ratio
Divide FTP watts by kilograms. Example: 260 W ÷ 72 kg = 3.61 W/kg. Two decimals help with arithmetic; they do not remove measurement uncertainty.
04
Add the missing context
Interpret the result with age, experience, event, duration and terrain. Use a complete power profile for training decisions and actual race results for competitive ability.

EXAMPLE CALCULATIONS

FTP calculation

· FTP: 280W
· Weight: 72kg

3.89 W/kg at FTP. The ratio does not by itself establish a race category or predict a gran fondo result.

Repeatable baseline

· FTP: 200W
· Weight: 88kg

2.27 W/kg at FTP. Record the method and date, then compare with the same setup after a suitable training period.

LIMITATIONS

The output is rider-only FTP W/kg, not total-system W/kg and not a speed prediction. It does not include bicycle mass, gradient, aerodynamic drag, wind, rolling resistance, drafting, pacing, fatigue or power-duration shape. The displayed ranges are not population percentiles, sex- or age-adjusted norms, race categories or medical advice.

When to see a coach

A coach can help when repeated, comparable tests do not move despite consistent training or when event demands are unclear. Intentional weight loss, persistent fatigue, falling power, menstrual disturbance, recurrent illness or injury should be handled with appropriately qualified medical or sports-dietetic support rather than a generic W/kg target.

SOURCES & TRUST

Author

Anthony Walsh — Cycling Coach & Podcast Host

Evidence sources

Creating Your Power Profile — Andrew Coggan · multi-duration framework and benchmark limits
Understanding Intensity: Power — British Cycling · FTP W/kg definition and weight-loss caution
Allometric scaling of uphill cycling performance — Jobson et al., 2008 · field hill-climb study
Optimal body-mass normalisation over complex cycling courses — Horvath and Andersson, 2025 · course-specific modelling
Power profiling and the power-duration relationship in cycling — Leo et al., 2022 · narrative review
IOC consensus statement on Relative Energy Deficiency in Sport — Mountjoy et al., 2023 · health and performance consensus

Reviewed by Anthony Walsh — coach review and source verification · Updated 26 August 2026

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FREQUENTLY ASKED QUESTIONS

What is a good W/kg for cycling?+

There is no context-free good number. Duration, test method, age, sex, training history and event all matter. Generic charts are useful for orientation, not as population percentiles or race categories. Compare against a matched age or experience reference and your own repeatable baseline.

How do I improve my W/kg?+

Increase sustainable power through appropriate training and recovery. Body-mass change is not automatically required and should preserve energy availability, health, recovery and useful power. A generic calculator cannot decide whether weight loss is appropriate for an individual.

Does W/kg matter on flat roads?+

Less than on sustained climbs. At higher speeds on flatter roads, absolute power and aerodynamic drag become more important. Wind, rolling resistance, drafting, position and course shape also matter, so W/kg is not a universal finishing-speed predictor.

Is FTP W/kg the same as climbing W/kg?+

Not necessarily. FTP is a threshold-related estimate, while a climb may last much less or much more time. Use power for a duration that matches the climb, then account for bicycle mass, gradient, aerodynamics and conditions.