Heart Rate Calculator
Calculate your maximum heart rate and target heart rate zones for fat burning, cardio, and peak performance.
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How to use this calculator
Heart rate zones are percentages of your maximum heart rate, each targeting different training adaptations.
- 1
Enter your age in years.
- 2
Enter your resting heart rate (measure first thing in the morning before getting up).
- 3
The calculator shows your max heart rate and all five training zones using the Karvonen (Heart Rate Reserve) method.
Frequently asked questions
Which formula gives the main maximum heart rate figure?
The highlighted figure is 220 minus your age, rounded. The Tanaka estimate, 208 minus 0.7 times your age, is shown as a second line for comparison only. The training zones are built from the 220 − age value, not from Tanaka.
How are the five zones calculated?
With the Karvonen heart-rate-reserve method. Reserve is the maximum heart rate minus your resting heart rate, and each boundary is resting rate + reserve × a percentage (50, 60, 70, 80, 90 and finally 100 per cent). So the percentages describe effort within your reserve, not a share of your raw maximum.
Why do my zones change when I change my resting heart rate?
Because the resting rate is the baseline of the Karvonen formula. At age 30, a resting rate of 65 puts the Zone 3 band at 153 to 165 bpm; the same age with a lower resting rate would move the band edges below the maximum down. A simple percentage of maximum would ignore resting rate entirely.
Why are the two maximum figures different?
They are different straight-line equations of age. They give the same answer at age 40 (180 bpm) and drift apart on either side: 190 versus 187 at age 30, 160 versus 166 at age 60. Neither is a measurement of your own maximum.
What happens with an impossible input?
If age is zero or negative, the resting rate is zero or negative, or the resting rate is at or above 220 minus your age, the calculator returns a short message asking for valid numbers instead of reversed or meaningless zones.
What do the zone names mean?
Warm-up, fat burn, cardio, hard and max are descriptive labels the tool attaches to ranges of effort. They are not clinical thresholds, and the calculator does not estimate calories burned or fat used in any zone.
Is it safe to train at the top zone?
The calculator cannot judge that. It does not know your fitness, heart health or medication, and age-based formulas can be well off for an individual. If you have a heart condition, take medicine that affects heart rate, or have symptoms during exercise, get advice from a doctor first. This is general information, not medical advice.
Heart rate zone calculator — Karvonen method and maximum heart rate
Two steps: a maximum, then a reserve
The calculator first estimates your maximum heart rate as 220 minus your age. It then subtracts your resting rate to get heart rate reserve, and places each zone boundary at resting rate plus a fixed share of that reserve. Because the same maximum is used for every zone, the numbers move with only two inputs, age and resting heart rate. A second maximum, from the Tanaka equation, appears alongside for comparison.
Worked examples
Three people were run through the calculator. Zone edges are shared, so the top of one zone equals the bottom of the next.
| Zone | Age 30, resting 65 | Age 45, resting 55 | Age 60, resting 70 |
|---|---|---|---|
| Max HR (220 − age) | 190 | 175 | 160 |
| Max HR (Tanaka) | 187 | 177 | 166 |
| Zone 1 (50–60%) | 128–140 | 115–127 | 115–124 |
| Zone 2 (60–70%) | 140–153 | 127–139 | 124–133 |
| Zone 3 (70–80%) | 153–165 | 139–151 | 133–142 |
| Zone 4 (80–90%) | 165–178 | 151–163 | 142–151 |
| Zone 5 (90–100%) | 178–190 | 163–175 | 151–160 |
Why Karvonen and not a flat percentage
A flat percentage of maximum treats everyone of the same age identically. The Karvonen approach lets fitness show up through resting heart rate: for the age-30 example the 50 per cent line is 128 bpm, higher than 95 bpm that half of 190 would suggest. That is because it adds the resting 65 bpm to half of the 125 bpm reserve. The method is a long-standing training convention, and its main strength is that two people of the same age can get different zones.
Which maximum to trust
Both equations are averages drawn from groups of people, so they describe a population better than any one person. The 220 − age line and the Tanaka line cross at 40 years old. Younger than that the simple rule gives the higher number, and older than that Tanaka does. The gap is only a few beats in the examples above, which is small compared with how far an individual’s true maximum can sit from either estimate. A supervised exercise test is the way to find your own.
Measuring resting rate and using the zones
Resting heart rate is best taken first thing in the morning, before getting out of bed, counting beats for a full minute or reading a wearable after you have been still for a while. Use the zones as rough effort bands alongside how hard the session feels. They do not account for heat, caffeine, illness, dehydration or medication such as beta blockers, all of which can shift heart rate. Anyone with a heart condition or exercise-related symptoms should take medical advice before training by numbers.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →