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Free indoor cycling tool

Indoor Cycling
Training Zone Calculator.

Enter your FTP or threshold heart rate to get your power zones in watts or heart rate zones in bpm for structured indoor training.

Your numbers
Tip: FTP is the power you can hold for about an hour, usually 95% of a 20-minute test. Threshold HR is your average heart rate over that same hard hour.
Your zones
FTP 200 W

Power zones use the Coggan model as a share of FTP; heart rate zones use a share of threshold heart rate. Zones are training guides, not exact physiological boundaries.

The maths

How the calculator works

Both methods anchor every zone to a single threshold number, then set each band as a percentage of it.

%
Power zones = a share of FTP. Zone 2 endurance is 56 to 75%, Zone 4 threshold is 91 to 105%, Zone 5 VO2 max is 106 to 120% of FTP.
bpm
Heart rate zones = a share of threshold heart rate. Endurance sits below about 89%, threshold work around 95 to 102%, with harder efforts above that.
FTP
Find your FTP = roughly 95% of your best 20-minute average power. It is the anchor for every power zone.
HR
Find threshold HR = your average heart rate over a hard, steady hour. More reliable for zones than a max-heart-rate formula.
Z
Train by zone = keep easy rides in Zone 2 and hard efforts in Zone 4 and up, so each session does its intended job.

Power reacts instantly and is best for interval structure; heart rate lags but confirms how your body is coping. Used together they give a complete picture of every indoor session.

Want a printable zone chart for the pain cave?
A one-page power and heart rate zone reference is coming soon to our shop.
FAQ

Indoor cycling training zone FAQ

Training zones split effort into bands from easy recovery to all-out, each with a distinct training purpose. Riding by zone keeps easy sessions easy and hard sessions hard, which is the backbone of structured indoor training and helps you improve without burning out.

Power zones respond instantly and are ideal on a smart trainer or power meter, making them the gold standard for intervals. Heart rate lags a minute or two behind effort but works on any bike with a chest strap. Many riders use power for the workout structure and heart rate as a cross-check.

This tool uses the Coggan seven-zone model based on a percentage of your FTP. For example Zone 2 endurance is 56 to 75 percent of FTP and Zone 4 threshold is 91 to 105 percent. Enter your FTP and it returns the exact watt range for every zone.

The heart rate zones are a percentage of your lactate threshold heart rate, the highest average you can hold for about an hour. This threshold-based method is more accurate for training than formulas built on maximum heart rate, because it reflects your actual fitness.

FTP, or functional threshold power, is the highest steady power you can sustain for roughly an hour. Most riders estimate it from a 20-minute test and take 95 percent of that average. Our FTP and power zones calculator walks through the full process.

A common balance is plenty of Zone 2 endurance to build aerobic base, regular Zone 4 threshold work to raise your ceiling, and shorter Zone 5 efforts for top-end power. The right mix depends on your goals, so follow a plan rather than living in the middle zones.