Target Heart Rate Calculator
Enter your age and resting heart rate. The calculator estimates your maximum heart rate as 220 minus your age, then lists five training zones in beats per minute, from 50% to 100% of your heart rate reserve. That is the Karvonen method, so your resting heart rate shapes every zone.
How to use the Target Heart Rate Calculator
- Enter your numbers in the Target Heart Rate Calculator above.
- Press the Calculate button to see the result.
- To try other numbers, change any value and press the button again.
The target heart rate formulas
Max HR = 220 − age · · · Heart rate reserve = Max HR − Rest HR · · · Target = Rest HR + Heart rate reserve × intensity
The calculator uses the Karvonen method, with 220 − age as the maximum. Each zone runs between two intensities: 50–60%, 60–70%, 70–80%, 80–90% and 90–100% of your heart rate reserve. Every limit is rounded to the nearest whole beat. Age and resting heart rate are read as whole numbers, and the resting rate has to be below the estimated maximum.
Worked example
A 40-year-old with a resting heart rate of 60 has an estimated maximum of 220 − 40 = 180 bpm and a heart rate reserve of 180 − 60 = 120. Zone 2 runs from 60 + 120 × 0.60 = 132 to 60 + 120 × 0.70 = 144 bpm. The full list reads 120–132, 132–144, 144–156, 156–168 and 168–180 bpm. Taking 60–70% of the maximum alone would give 108–126 bpm, which is lower because it leaves the resting heart rate out.
Frequently asked questions
How accurate is the 220-age formula?
Tanaka, Monahan and Seals tested it in a paper published in 2001. They pooled group averages from 351 studies with 18,712 subjects, then measured maximum heart rate in 514 healthy adults in a lab. Age tracked the group averages closely, with a correlation of −0.90, and the line that fit best was 208 − 0.7 × age. Their findings suggest that 220 − age underestimates maximum heart rate in older adults. The two formulas agree at age 40. At 70, 220 − age gives 150 BPM and the Tanaka line gives 159. Both describe the average for your age, and your own maximum can sit above or below it. Source: Journal of the American College of Cardiology, volume 37, issue 1.
What is zone 2 on this calculator?
Zone 2 is 60–70% of your heart rate reserve added to your resting heart rate. Some charts and watches define zone 2 as 60–70% of maximum heart rate instead, which gives lower numbers. For a 40-year-old resting at 60 bpm the calculator shows 132–144 bpm, while 60–70% of the maximum is 108–126 bpm.
Why does my resting heart rate change the zones?
Each zone starts from your resting heart rate and adds a share of the gap up to your estimated maximum. Two 40-year-olds, one resting at 50 bpm and one at 70, get Zone 2 at 128–141 bpm and 136–147 bpm. The top of Zone 5 is the estimated maximum for both, 180 bpm.