How does the heart rate calculator work?
- Enter your age. The calculator uses it to estimate your maximum heart rate.
- Choose a formula. 220 minus age is the classic. The Tanaka formula, 208 minus 0.7 times age, is the alternative covered below.
- Add a measured maximum if you have one. A figure from a supervised exercise test replaces the estimate. Most people leave this blank.
- Read your zones. Each zone shows a range in beats a minute and the same range as a 10-second pulse count.
- Check yourself mid-workout. Count your pulse for 10 seconds and compare it with the 10-second figure, or use the talk test.
The calculator runs in your browser and stores nothing.
What are the heart rate zones for exercise?
Each zone is a share of your maximum heart rate. A 2014 study in PLoS One used the standard cut-offs: 50 to 63 percent of maximum for light effort, 64 to 76 percent for moderate, and 77 to 93 percent for vigorous. Here is what that looks like for a 50-year-old, whose estimated maximum is 170 using 220 minus age:
| Zone | Share of maximum | Example: age 50 |
|---|---|---|
| Light | 50 to 63% | 85 to 107 beats a minute |
| Moderate | 64 to 76% | 109 to 129 beats a minute |
| Vigorous | 77 to 93% | 131 to 158 beats a minute |
Moderate is the zone most activity guidelines are built around, which is why it is the one to learn. For how many minutes a week are recommended, read how much exercise you actually need.
Which maximum heart rate formula is more accurate?
Neither is exact, and the difference depends on your age. A 2024 review in the Journal of Clinical Medicine explains that 220 minus age was "obtained from a cohort of men with an average age of 55 years" and "tends to overestimate the APMHR in young adults and underestimate it in older adults, notably after the age of 40." APMHR is age-predicted maximum heart rate.
The Tanaka formula was "derived from 351 studies involving 18,712 participants". It is still an estimate, with "a standard error of estimate around 11.4 bpm", so your true maximum can easily sit 10 or more beats either side of it. The review also notes that the people behind it were healthy and free of coronary artery disease, which limits how well it applies to anyone who is not.
| Age | 220 minus age | Tanaka formula |
|---|---|---|
| 20 | 200 | 194 |
| 30 | 190 | 187 |
| 40 | 180 | 180 |
| 50 | 170 | 173 |
| 60 | 160 | 166 |
| 70 | 150 | 159 |
The two formulas agree at 40. Below that, the classic formula gives the higher figure; above it, Tanaka does. If you are over 40, it is worth switching the calculator to Tanaka and seeing how much your zones move.
Are you exercising as hard as you think?
Probably not, if you are aiming for moderate. In the PLoS One study, people asked to exercise at different efforts "correctly estimated light effort as 51.5±8.3%HRmax but underestimated moderate effort as 58.7±10.7%HRmax and vigorous effort as 69.9±11.9%HRmax."
In plain terms: when people chose what felt like moderate effort, they landed on average in the light zone. When they chose vigorous, they landed in moderate. That is the most practical reason to use a number, or the talk test, rather than feel alone.
How do you check your heart rate without a monitor?
Two ways. Count your pulse at your wrist or neck for 10 seconds and compare it with the 10-second figure the calculator gives you. Or use the talk test, which the CDC describes this way: "a person doing moderate-intensity aerobic activity can talk, but not sing, during the activity. A person doing vigorous-intensity activity cannot say more than a few words without pausing for a breath."
The talk test needs no maths and adjusts to you automatically, which makes it a useful check on any formula. If your watch says moderate but you can sing comfortably, trust the singing.
When do these heart rate zones not apply?
- If you take medicine that slows your heart. The NHS explains that beta blockers work by "slowing down your heartbeat", so age-based zones will overstate what you can reach. Use the talk test and ask your doctor.
- If you have a heart condition. Ask your doctor or cardiac rehab team what range suits you rather than using an age formula.
- If something feels wrong. Chest pain, unusual breathlessness or dizziness during exercise are reasons to stop and get medical advice, whatever the numbers say.
For ways to build more movement into an ordinary day, see movement snacks for a desk-bound day and whether sitting all day cancels out your workout. The full guide to movement puts it all together.
