Your max heart rate and 5 training zones, from age or from age and resting heart rate.
Estimate only, not medical advice.
Five zones, defined as a percentage band of your max heart rate, are the standard way endurance coaches split up training intensity. Below is what those bands look like for a 40-year-old with a max heart rate of 180 (220 minus 40); enter your own age above to see your version.
| Zone | % of max | Range (bpm) |
|---|---|---|
| Zone 1, Recovery | 50-60% | 90-108 |
| Zone 2, Easy | 60-70% | 108-126 |
| Zone 3, Aerobic | 70-80% | 126-144 |
| Zone 4, Threshold | 80-90% | 144-162 |
| Zone 5, Max effort | 90-100% | 162-180 |
Same 50/60/70/80/90/100 percent breakpoints the calculator above applies to your own max heart rate.
Leave the resting heart rate field blank and this uses the 220-minus-age formula, sometimes credited to a 1970s study by Fox and colleagues, applied straight to your max heart rate. Add a resting heart rate, measured first thing in the morning before you get out of bed, and it switches to the Karvonen method, which works from your heart rate reserve (max minus resting) instead. Karvonen tends to produce slightly higher zone floors for fitter people, since a lower resting heart rate widens the reserve the percentages are calculated from.
It's a population average, not a measurement of you specifically, popularized by research attributed to Fox and colleagues in the 1970s. A lab test with a graded exercise protocol is more accurate, but this formula is close enough for setting training zones for most people.
It factors in your resting heart rate, which reflects your current fitness. Two people with the same age and max heart rate can have very different resting rates, and Karvonen's heart-rate-reserve method accounts for that difference when it sets your zones.
That's the point. Zone 2 is built for a pace you can hold for a long time while still being able to talk, and most of a distance runner's weekly volume is supposed to live there, not in the harder zones.
No. It's a population average with a fairly wide error range for any one person, wider than most people expect. If your zones feel consistently too easy or too hard at the percentages shown, trust how the effort feels over the formula.