How to use the heart rate zone calculator
- Enter your Age (10–100) and your Resting heart rate in bpm.
- Under Maximum heart rate, choose 220 − age, 208 − 0.7 × age (Tanaka), or I know my measured maximum, then type your Measured maximum if you have one.
- Under Zones based on, choose Heart-rate reserve (Karvonen) or % of maximum.
- Read the Maximum heart rate, Heart-rate reserve and Resting heart rate, then the five zones in the Training zones table.
What it does and when to use it
Many runners, cyclists and gym users train by heart rate: easy days in a low zone, hard intervals in a high one. A watch or chest strap shows your pulse, but you need targets to compare it with. This calculator turns your age and resting pulse into five ranges in beats per minute.
The five zones used are:
| Zone | Intensity | Share of reserve or maximum |
|---|---|---|
| 1 | Very light (recovery) | 50–60% |
| 2 | Light (base endurance) | 60–70% |
| 3 | Moderate (aerobic) | 70–80% |
| 4 | Hard (threshold) | 80–90% |
| 5 | Maximum | 90–100% |
Training plans and devices use slightly different zone names and boundaries, so check what your plan expects. To set a race pace to go with the zones, use the pace calculator. For an estimate of aerobic fitness from heart rate, see the VO2 max calculator, and for blood pressure readings, the blood pressure classifier.
How it works
Maximum heart rate comes from your choice:
- 220 − age
- 208 − 0.7 × age (Tanaka et al., 2001)
- your measured maximum
Heart-rate reserve = maximum − resting.
Each zone boundary at percentage p is then:
- Karvonen: resting + (maximum − resting) × p ÷ 100
- % of maximum: maximum × p ÷ 100
Values are rounded to whole beats. Karvonen zones are always higher than %-of-max zones at the same percentage, because they start from your resting rate rather than from zero.
Worked examples
These figures come from the calculator’s own function.
Age 40, resting 60, 220 − age, Karvonen. Maximum 180 bpm, reserve 120 bpm. Zone 1 is 120–132 bpm, zone 2 is 132–144 bpm, zone 3 is 144–156 bpm, zone 4 is 156–168 bpm and zone 5 is 168–180 bpm.
Same person, % of maximum. Zone 1 is 90–108 bpm and zone 2 is 108–126 bpm. Notice how much lower these are than the Karvonen zones; pick one method and stick with it.
Age 60, resting 65, Tanaka, Karvonen. Maximum 166 bpm (208 − 42), reserve 101 bpm. Zone 2 is 126–136 bpm. With 220 − age the maximum would be 160 bpm instead.
Limits and tips
- Formulas are averages. The calculator’s own note warns that an age-based maximum can be 10–20 bpm off for an individual.
- Medicines matter. Beta blockers and some other medicines lower heart rate, which makes formula-based zones unreliable.
- Heat, caffeine, stress and poor sleep all raise heart rate on the day.
- This is general fitness information, not medical advice. Everything is calculated in your browser.
Frequently asked questions
Which maximum heart rate formula should I pick?
What is heart-rate reserve?
How do I measure my resting heart rate?
Is it safe to train in zone 5?
Sources
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001;37(1):153-6 — Journal of the American College of Cardiology (via PubMed, U.S. National Library of Medicine), accessed 2026-10-07
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