How to use it
Enter your age and the calculator instantly estimates your maximum heart rate and splits it into five training zones. Your max heart rate uses the Tanaka formula, 208 − 0.7 × age, which fits most adults better than the older “220 − age” rule.
For sharper numbers, tap Go advanced and add your resting heart rate. That switches the zones to the Karvonen (heart-rate-reserve) method, which personalises each zone to your own fitness. You can also override the estimated max if you know yours from a lab or field test.
Why Zone 2 gets all the attention
Zone 2 is where most endurance training happens. It’s easy enough to sustain, trains your body to burn fat efficiently, and builds the aerobic base everything else is built on. If you only remember one number, remember your Zone 2 range.
%-of-max vs Karvonen
The simple method takes a straight percentage of your maximum heart rate. The Karvonen method uses your heart-rate reserve — the gap between max and resting heart rate — so a fitter person with a low resting pulse gets zones tuned to them. Both are estimates; a lab test is the gold standard.
What the five zones mean
| Zone | % of max | Feels like |
|---|---|---|
| Zone 1 · Recovery | 50–60% | very easy |
| Zone 2 · Endurance | 60–70% | fat burn · base |
| Zone 3 · Tempo | 70–80% | moderately hard |
| Zone 4 · Threshold | 80–90% | hard |
| Zone 5 · VO₂ max | 90–100% | maximum |
Training by pace instead?
If you plan runs by pace rather than heart rate, our Pace Calculator solves pace, time or distance and predicts your finish times and splits.
A good resting heart rate
Measure your pulse first thing in the morning before getting up. Most adults sit between 55 and 75 bpm; well-trained endurance athletes are often lower.
Common questions
How is my maximum heart rate calculated?
By default we use the Tanaka formula, 208 − 0.7 × age. It fits most adults better than “220 − age.” If you know your true max from a test, enter it in advanced mode to override the estimate.
What is Zone 2 heart rate?
Zone 2 sits at roughly 60–70% of your maximum heart rate (or heart-rate reserve with Karvonen). It’s the aerobic, fat-burning zone — an easy, conversational effort you can hold for a long time.
Which is more accurate, %-of-max or Karvonen?
Karvonen is usually more personalised because it factors in your resting heart rate. Both are estimates; only a lab or field test gives your true numbers.
What’s a good resting heart rate to enter?
Measure your pulse first thing in the morning before getting up. Most adults fall between 55 and 75 bpm; well-trained endurance athletes can be lower.