Heart rate zone calculator for runners

Set your running heart-rate zones from your maximum and resting heart rate: easy, long run, steady, marathon pace, marathon race day and threshold, in beats per minute.

How the calculator works

It uses heart-rate reserve, the gap between your maximum and resting heart rate. This is often called the Karvonen method, after a 1957 study of training and heart rate by Karvonen, Kentala and Mustala. Each zone starts at your resting heart rate and adds a share of the reserve.

With a maximum of 196 and a resting heart rate of 50, the reserve is 146 beats. Easy running at 60–68.5% of the reserve is 138–150 beats per minute. Threshold at 81–86% is 168–176. The percentages are the ones coach steve uses in its own plans.

Using the reserve rather than a percentage of maximum alone means two runners with the same maximum but different resting heart rates get different zones, which accounts for that difference.

Finding your maximum heart rate

The best number is the highest heart rate you have actually seen, for example at the end of a hard race or a hill repeat session on a chest strap. If you do not know it, the calculator can estimate it from your age with the formula 208 − 0.7 × age, from a 2001 analysis by Tanaka, Monahan and Seals of 351 studies. Read “Age-predicted maximal heart rate revisited”. An age formula predicts the average for people your age; your own maximum can be well above or below it, and every zone moves with it.

Finding your resting heart rate

Use a morning reading taken lying down before you get up, or the resting heart rate your watch reports, averaged over a week. One reading after a poor night or a hard day will be high.

When heart rate misleads

Heart rate rises in heat, with dehydration, at altitude and late in long runs, even at the same pace. Wrist sensors can also read high or low, especially in intervals. Treat the zones as a guide and check them against how the run feels. Paces for the same runs are in the training pace calculator.

From zones to training

Zones tell you how hard. A plan tells you how often. We make coach steve, an AI running coach you can text, designed to use your available Garmin data, heart rate included, when you talk a run through.

Common questions

Why are there two marathon zones?

Marathon pace is the effort you train at for the race. The race-day band is narrower, with a lower ceiling, to hold the first half back so the second half is still there.

Should I use 220 minus age?

The Tanaka study found that formula underestimates maximum heart rate in older adults. A measured maximum beats both.

Where are my numbers saved?

Nowhere. The calculator keeps them in the page while it is open.