Cycling Power Zones Calculator

How to use the cycling power zones calculator

What this calculator does

This calculator converts Current FTP, measured in watts, into five power-based training zones. FTP means functional threshold power: a practical estimate of the highest steady cycling power you can sustain for roughly an hour. The calculator uses FTP as a common reference point, then places recovery, endurance, tempo, threshold, and very hard work into percentage bands. It helps you set targets on a bike computer, smart trainer, or workout plan. It does not determine whether a workout is medically appropriate, predict race performance, or replace a coach, laboratory assessment, or careful interpretation of fatigue and environmental conditions. Garmin's overview of functional threshold power and FTP-based training intensity explains why FTP is useful as a repeatable performance marker.

When to use it

Use this tool after an FTP test, when updating zones in a cycling computer, when designing structured intervals, or when checking whether a ride matched its intended intensity. It is especially useful for distinguishing easy endurance work from tempo riding that accumulates more fatigue, and for setting a threshold range around FTP rather than treating one watt value as a rigid physiological border. British Cycling recommends athlete-specific testing because training zones should reflect the rider's current physiology; its guide to understanding cycling intensity and individualized zones provides additional context.

How to calculate

1. The calculator opens with a complete demonstration input of 250 W. Finite zone results are already displayed, and the example Excel workbook is available immediately.
2. Replace 250 in Current FTP with your own tested or estimated value. Enter digits only, from 40 through 700 W. Do not include “W”, commas, decimals, signs, or scientific notation.
3. Read the summary pills, the highlighted Zone 4 · Threshold result, the five zone cards, and the Complete zone table. Every result updates live from the same calculation.
4. Select Download Excel to export the current FTP, zone boundaries, RPE bands, purposes, and methodology as a validated .xlsx workbook. Select Reset to clear the demonstration value and calculated content. Reset may disable Excel export until a complete valid FTP is entered again.

Input guide

Current FTP is required. It must be a whole-number cycling power in watts, with an accepted range of 40 – 700 W; 250 W is the startup example. Increasing FTP raises every watt boundary proportionally, while decreasing FTP lowers every boundary. A common mistake is entering the average power from a 20-minute test without applying the test protocol's conversion. One widely used convention estimates FTP as 95% of a maximal 20-minute average, while ramp-test protocols use a different relationship. Keep the method consistent when comparing results over time. Garmin's cycling training zones guide discusses several credible FTP testing approaches and notes that FTP remains an estimate rather than an immutable daily value.

Output guide

FTP repeats the accepted watt input. Endurance is Zone 2, the 56% – 75% band used for steady aerobic riding. Threshold and Zone 4 · Threshold show the 91% – 105% range around FTP. Each zone card and table row displays the exact Power range, its Percent of FTP, a RPE range on a 1 – 10 perceived-exertion scale, and a Typical purpose. Zone 1 is shown as an upper ceiling because it begins at zero practical output, while Zone 5 is shown with a plus sign because it has no calculated upper limit. These watt ranges are estimates and planning categories, not separate physiological switches; actual sensations and sustainable duration vary by athlete, temperature, fatigue, altitude, nutrition, and test accuracy.

Worked example

With the startup FTP of 250 W, Zone 1 ends at 138 W because 250 × 0.55 = 137.5, rounded to the nearest whole watt. Zone 2 then begins at 139 W and ends at 188 W, based on 250 × 0.75 = 187.5. Zone 3 is 189 – 225 W, Zone 4 is 226 – 263 W, and Zone 5 begins at 264 W. The contiguous boundaries prevent one-watt gaps after rounding. At this FTP, a 170 W endurance target sits within Zone 2, whereas a 250 W interval is inside Zone 4. The Excel workbook contains these same typed values rather than copying rounded text from the page.

Learn more

The five-zone structure is a practical simplification of the commonly used FTP percentage framework. For a more granular comparison, TrainingPeaks explains power-based training levels and their physiological purposes. Different platforms may split high-intensity work into additional VO₂ max, anaerobic-capacity, and neuromuscular zones, so use one method consistently inside a training plan instead of mixing boundaries from several systems.