Shed

Free tool · Heart rate

Heart Rate Zone Calculator

Five training zones from your maximum, your heart rate reserve, or your threshold heart rate. Pick the method you can actually measure, because zones built on a guessed maximum are a guess with decimal places.

Method

Straight percentages of your maximum. Simplest, and the least accurate if your max is a guess.

Your zones

  • Zone 1 · Recovery

    Warm-ups, cool-downs, shake-out runs

    95–114

  • Zone 2 · Easy

    The bulk of your weekly volume

    114–143

  • Zone 3 · Steady

    The grey zone. Use sparingly

    143–162

  • Zone 4 · Threshold

    Tempo runs and cruise intervals

    162–175

  • Zone 5 · VO₂max

    Intervals of 3 to 5 minutes

    175–190

Zone 2 is highlighted because it is where most of your week should be. If your easy runs are consistently landing in zone 3, they are too fast.

Stop calculating. Start training.

These numbers are the first 30 seconds of what Shed does.

Shed reads your Apple Health, grounds your VDOT in your actual training — not one race — and writes the whole block: every workout, every pace, adjusted as life happens. The calculator gives you a snapshot; Shed gives you the plan.

Get your plan on iPhone

What the five zones are for

Zone 1 is recovery: warm-ups, cool-downs and shake-out runs. Zone 2 is where the majority of your weekly volume belongs, and it is the zone most runners spend the least time in. Zone 3 is the grey zone, hard enough to accumulate fatigue and too easy to drive much adaptation. Zone 4 is threshold, the intensity of tempo runs and cruise intervals. Zone 5 is VO₂max, reached in intervals of three to five minutes.

A well-built week is roughly 80 percent zones 1 and 2 by time, with the remainder in zones 4 and 5. Very little should be in zone 3 on purpose.

Why 220 minus age is a poor starting point

The formula was never designed as a training tool. It was a rough line fitted through population data, and the spread around it is wide enough that an individual runner can be 20 beats out in either direction. Twenty beats moves every zone boundary, which means easy runs prescribed too slow to be useful or threshold sessions prescribed hard enough to be counterproductive.

It is a particularly poor fit for masters runners, where the variation between individuals grows. If you are over 40 and training by heart rate, measuring your own maximum or your threshold is worth the one hard session it costs.

Frequently asked

How do I find my maximum heart rate?
From a real maximal effort, not a formula. The highest reading you have seen in a hard 5K race or a session of hard hill repeats is usually within a beat or two of your true maximum. The 220 minus age formula has a standard deviation of roughly 10 to 12 beats, which means it can easily be 20 out for an individual runner.
Which method should I use?
Threshold, if you can measure it. Run a hard 30 minute time trial alone and take your average heart rate over the last 20 minutes. It anchors the zones to a physiological point that actually matters, rather than to a maximum most runners have never truly measured.
What is heart rate reserve?
The Karvonen method. It uses the range between your resting and maximum heart rate rather than max alone, which accounts for individual differences in resting heart rate. A percentage of reserve is added to your resting rate to get the zone boundary.
Why is my heart rate higher than usual today?
Heat, dehydration, poor sleep, caffeine, illness or stress all raise heart rate at a given pace. On a hot day your zone 2 pace can be 45 seconds per mile slower than usual, and that is the heart rate being right about your body rather than wrong about your fitness.
Should I train by heart rate or pace?
Pace for hard sessions, where you want a specific intensity and heart rate lags behind the effort. Heart rate for easy runs, where it stops you drifting too fast, and on hot days when pace no longer reflects effort.

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