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whatsmypulse

Heart rate zone calculator

Five training zones from your age, with your resting heart rate if you know it. Every maximum-heart-rate equation is shown side by side, because they disagree by more than people expect.

Zones calculator

Years, 18–90

bpm, measured after resting

Only if you know it from a test

Enter your age to see the results. Everything is calculated in this page; nothing is sent.

Where the five zones come from

The familiar five zones, from 50–60% up to 90–100% of maximum heart rate in steps of ten, are a convention of heart-rate-monitor makers. Polar names them very light, light, moderate, hard and maximum[1]; Garmin uses the same percentages with the labels warm-up, easy, aerobic, threshold and maximum[2]. Public-health bodies describe intensity differently, in two or three broad bands (moderate and vigorous), which you will find on the target heart rate page. The zone names and the “how it feels” notes in the table follow these manufacturer guides.

Two ways to turn percentages into beats

Percentage of maximum multiplies your maximum heart rate by each percentage. It needs only your age, and it is what the device guides above describe.

Percentage of heart rate reserve, also called the Karvonen method after the Finnish physiologist whose 1957 training study introduced it[3], starts from your resting heart rate and adds a share of the gap between resting and maximum: target = resting + (maximum − resting) × percentage. Two people of the same age get different zones if one rests at 52 and the other at 78, so the zones follow your own heart rather than an average one. Enter a resting rate above and the calculator switches to this method automatically. The Karvonen formula page walks through the arithmetic.

The two methods give noticeably different numbers. At age 40 with a resting rate of 60, zone 2 by percentage of maximum (Tanaka) is 108–125 bpm, while zone 2 by reserve is 132–143 bpm. Neither is wrong; they are different scales, so stick with one and don’t mix advice written for the other.

Which maximum heart rate equation?

All the equations are averages fitted to groups of people. The most widely used, 220 minus age, was not fitted statistically at all: it was drawn by eye through about 35 published data points in 1971[4][5]. Tanaka’s 208 − 0.7 × age came from a meta-analysis of 351 studies covering 18,712 people and was confirmed in a lab study of 514 healthy adults[6]. Gellish followed 132 adults through 908 treadmill tests[7], Nes fitted 3,320 healthy Norwegians[8], and Gulati’s equation comes from 5,437 women[9]. The calculator uses Tanaka by default; switch the equation to see how much your zones move.

Individual people scatter around every one of these lines. Tanaka reports a standard deviation of about 10 beats per minute[6] and Nes a standard error of 10.8[8], so a 40-year-old whose true maximum is 172 or 196 is perfectly ordinary. If you have a measured maximum from an exercise test, enter it and it replaces the estimate.

A joint ACSM and ESSA statement from 2025 makes the same point from the other side: prescribing exercise as fixed percentages of maximum or reserve puts different people into different real intensity categories[10]. Use the zones as a starting point, and check them against how the effort feels.

Using the zones

The Physical Activity Guidelines for Americans recommend 150 to 300 minutes a week of moderate-intensity aerobic activity, or 75 to 150 minutes of vigorous activity, or a mix of the two[11]. A quick self-check that needs no numbers is the talk test: during moderate activity you can talk but not sing, and during vigorous activity you can’t say more than a few words without pausing for breath[12].

Some medicines change heart rate; the AHA notes, for example, that beta blockers can slow it[13]. If you take medication that affects your pulse, or have a heart condition, ask your clinician which targets suit you instead of relying on an age formula.

Questions people ask

What is the most accurate maximum heart rate formula?

None fits individuals well. Tanaka’s equation rests on far more data than 220 − age, and by age 70 the two already differ by about 10 bpm; either way, individuals scatter by about 10 bpm around the line[6][8].

Should I enter my resting heart rate?

If you know it, yes. It moves the zones to fit your own fitness. Measure it in the morning or after sitting quietly for about 10 minutes, ideally on a few days, and use a typical value.

Why are my watch’s zones different?

Watches may use a different maximum (often 220 − age, or one learned from your workouts), the reserve method, or different zone boundaries. Compare the settings, not just the numbers.

Do these zones apply to children?

No. The equations were fitted to adults, which is why the calculator accepts ages 18 to 90.

Is zone 2 the “fat-burning zone”?

Zone 2 here is simply 60–70% of maximum or of reserve. Research reviews have questioned whether a special zone 2 benefit exists; see the zone 2 page for the details.

Can I get these numbers from an API?

Yes, the same calculation is available as JSON at /api/zones, documented on the API page.

Sources

  1. Polar. Heart rate zones: the basics (training guide). polar.com. Checked 2026-10-09.
  2. Garmin. How you can train by heart rate zones using Garmin (blog, Mar 28, 2025). garmin.com. Checked 2026-10-09.
  3. Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 1957;35(3):307–315. PubMed 13470504. Checked 2026-10-09.
  4. Fox SM, Naughton JP, Haskell WL. Physical activity and the prevention of coronary heart disease. Ann Clin Res 1971;3(6):404–432 (as reproduced and analysed by Robergs & Landwehr 2002). PubMed 4945367. Checked 2026-10-09.
  5. Robergs RA, Landwehr R. The surprising history of the “HRmax = 220 − age” equation. J Exerc Physiol Online 2002;5(2):1–10. asep.org. Checked 2026-10-09.
  6. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 2001;37(1):153–156. doi:10.1016/S0735-1097(00)01054-8. Checked 2026-10-09.
  7. Gellish RL, Goslin BR, Olson RE, et al. Longitudinal modeling of the relationship between age and maximal heart rate. Med Sci Sports Exerc 2007;39(5):822–829. doi:10.1097/mss.0b013e31803349c6. Checked 2026-10-09.
  8. Nes BM, Janszky I, Wisløff U, Støylen A, Karlsen T. Age-predicted maximal heart rate in healthy subjects: the HUNT fitness study. Scand J Med Sci Sports 2013;23(6):697–704. doi:10.1111/j.1600-0838.2012.01445.x. Checked 2026-10-09.
  9. Gulati M, Shaw LJ, Thisted RA, et al. Heart rate response to exercise stress testing in asymptomatic women: the St. James Women Take Heart Project. Circulation 2010;122(2):130–137. doi:10.1161/CIRCULATIONAHA.110.939249. Checked 2026-10-09.
  10. Bishop DJ, et al. Physical activity and exercise intensity terminology: a joint ACSM Expert Statement and ESSA Consensus Statement. Med Sci Sports Exerc 2025;57(11):2599–2613 — Table 1, column “ACSM (2020)”, i.e. ACSM’s Guidelines for Exercise Testing and Prescription, 11th ed. doi:10.1249/mss.0000000000003795. Checked 2026-10-09.
  11. U.S. Department of Health and Human Services. Physical Activity Guidelines for Americans, 2nd edition, 2018 (pp. 20, 56, 60, 109). odphp.health.gov. Checked 2026-10-09.
  12. Centers for Disease Control and Prevention. How to Measure Physical Activity Intensity (updated Dec 4, 2025). cdc.gov. Checked 2026-10-09.
  13. American Heart Association. All About Heart Rate (Pulse) (last reviewed May 13, 2024). heart.org. Checked 2026-10-09.