Heart rate zones calculator (Karvonen)
Your maximum heart rate and your five training zones using the Karvonen method, with the formula of your choice.
Calculator inputs
Results
Enter your values and press “Calculate” to see the result.
| Zone | % of reserve | Beats per minute | Effort |
|---|---|---|---|
| Z1 | 50–60 | 122–134 | Very light |
| Z2 | 60–70 | 134–146 | Light (aerobic base) |
| Z3 | 70–80 | 146–159 | Moderate (aerobic) |
| Z4 | 80–90 | 159–171 | Hard (threshold) |
| Z5 | 90–100 | 171–184 | Maximum |
| Formula | Estimated max HR |
|---|---|
| Tanaka (208 − 0,7 × edad) | 184 |
| Fox (220 − edad) | 185 |
| Gellish (207 − 0,7 × edad) | 183 |
| HUNT (211 − 0,64 × edad) | 189 |
See the working step by step
- Z1 = 122–134; Z2 = 134–146; Z3 = 146–159; Z4 = 159–171; Z5 = 171–184 bpm
In short
- What it calculates
- Your maximum heart rate and your five training zones using the Karvonen method, with the formula of your choice.
- Formula used
Max HR: Tanaka 208 − 0.7 × age · Fox 220 − age · Gellish 207 − 0.7 × age · HUNT 211 − 0.64 × age- Example
- Example 1. A 35-year-old.
Heart rate zones calculator
Training at the right intensity matters more than training more: too easy does not improve fitness, and too hard every day wears you out. Heart rate zones translate intensity into beats per minute, which you can follow with a watch or a chest strap.
Enter your age and your resting pulse. The calculator estimates your maximum heart rate with the formula you choose (or uses the one you have measured) and splits the heart rate reserve into five zones with the Karvonen method, which tailors each zone to your fitness. Everything runs in your browser.
How it works
Maximum heart rate is estimated with an age-based formula (the classic “220 − age” or the newer Tanaka, Gellish and HUNT ones). Heart rate reserve is the difference between the maximum and the resting rate.
The Karvonen method works out each zone as resting pulse + a percentage of the reserve. So two people of the same age with different resting pulses get different zones, something the simple percentage-of-max method does not reflect.
Formula
Max HR: Tanaka 208 − 0.7 × age · Fox 220 − age · Gellish 207 − 0.7 × age · HUNT 211 − 0.64 × age
Reserve = max HR − resting HR
Zone = resting HR + reserve × percentage
Z1 50–60% · Z2 60–70% · Z3 70–80% · Z4 80–90% · Z5 90–100% of the reserve
Worked example
Example 1. A 35-year-old.
With a resting pulse of 60 and the Tanaka formula, max HR is 183.5 bpm and the reserve is 123.5. Zones: Z1 122–134, Z2 134–146, Z3 146–159, Z4 159–171 and Z5 171–184 bpm. The aerobic-base zone (Z2) is 134 to 146 bpm.
Example 2. With the classic formula.
The same person with “220 − age” would have a max HR of 185 bpm and Z3 would run from 148 to 160 bpm, two beats above Tanaka’s: formulas differ by a few beats.
Example 3. With a measured max HR.
A 45-year-old with a resting pulse of 58 and a max measured in an exercise test of 178 bpm: the reserve is 120 and Z3 runs from 142 to 154 bpm. With the real measurement, zones are more reliable than with any formula.
Explanation
What heart rate zones are
They are pulse ranges that correspond to different effort intensities. Each zone trains a different quality: easy ones build the aerobic base and can be done for many hours; hard ones improve threshold and power, but tire you more and should be few.
The five zones
- **Z1 (50–60%)**: very light, warm-up and recovery.
- **Z2 (60–70%)**: aerobic base; you can hold a conversation. It is the zone for most endurance training.
- **Z3 (70–80%)**: moderate aerobic; sustained effort.
- **Z4 (80–90%)**: threshold; uncomfortable, for long intervals.
- **Z5 (90–100%)**: maximum effort, only in short intervals.
Karvonen or simple percentage
The simple percentage multiplies max HR by a percentage. Karvonen adds the resting pulse and applies the percentage to the reserve, which fits zones better to a trained person (with a low resting pulse) than to a sedentary one.
How far to trust the formula
Max HR varies a lot between people of the same age: the formulas’ standard deviation is about 10 bpm. Zones are a guide, not a border. Perceived effort (whether you can talk) and a real measurement in an exercise test improve accuracy.
Common mistakes
- Taking the formula as an exact value.
- Always training in the middle zone (“neither easy nor hard”).
- Measuring resting pulse after caffeine or activity.
- Using “220 − age” after 40 without checking it.
- Ignoring medication (such as beta blockers), which lowers heart rate.
Limits of this calculator
- Max HR is a statistical estimate; it does not replace an exercise test.
- It does not adjust for sport (max HR is slightly lower in cycling or swimming than running) or for medication or illness.
- Zones use the classic five-zone split; some systems use other percentages.
Notice
Talk to a health professional before starting an intense exercise programme, especially if you have heart problems, take medication or have not trained for a long time.
Frequently asked questions
How do I calculate my maximum heart rate?
The most accurate way is an exercise test. Without one, it is estimated with an age-based formula such as Tanaka’s (208 − 0.7 × age); none is exact.
What is the Karvonen method?
It works out each zone as the resting pulse plus a percentage of the reserve (max minus resting). It tailors zones to your fitness.
Which zone burns the most fat?
Zone 2 (easy, 60–70% of reserve) uses proportionally more fat, but what matters most for weight loss is total calories burned.
Is the 220 − age formula valid?
It is the best known but has a large error. The Tanaka, Gellish and HUNT formulas fit better across life.
How do I measure my resting pulse?
As soon as you wake, lying down, count your pulse for a minute. Repeat over several days and use the average.
Why does my watch show different zones?
Each maker uses its own method (percentage of max, of reserve or of threshold) and its own estimate of the maximum.
Can I use it if I take medication?
Some drugs, such as beta blockers, lower max heart rate and the formulas stop being valid. Ask your doctor.
Is my data sent to a server?
No. The calculation runs in your browser.
Sources and references
The formula behind this calculator is not ours. These are the sources it comes from, in APA 7 format, in case you want to go to the original or cite them in your own work.
- Tanaka, H., Monahan, K. D., & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1), 153–156. https://doi.org/10.1016/S0735-1097(00)01054-8 https://doi.org/10.1016/S0735-1097(00)01054-8 The 208 − 0.7 × age formula and how it differs from “220 − age”.
- Gellish, R. L., Goslin, B. R., Olson, R. E., McDonald, A., Russi, G. D., & Moudgil, V. K. (2007). Longitudinal modeling of the relationship between age and maximal heart rate. Medicine & Science in Sports & Exercise, 39(5), 822–829. https://doi.org/10.1249/mss.0b013e31803349c6 https://doi.org/10.1249/mss.0b013e31803349c6 The 207 − 0.7 × age formula, from longitudinal data.
- Karvonen, M. J., Kentala, E., & Mustala, O. (1957). The effects of training on heart rate: A longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3), 307–315. The heart rate reserve method, which tunes the zones to your resting pulse.
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