Heart Rate Zone Calculator (Karvonen)
Your maximum heart rate and training zones in bpm, by Karvonen or % of max.
Enter your age.
Your five training zones
| Zone | Heart rate | Beats in 30 s | Intensity | Typical use |
|---|
AHA and ACSM intensity ranges
| Range | Heart rate | Beats in 30 s | Defined as |
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Maximum heart rate by formula
| Formula | Maximum | Working |
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For general information only, not medical advice. Consult a qualified health professional for advice about your situation.
About the Heart Rate Zone Calculator (Karvonen)
Heart-rate zones turn “how hard am I working?” into numbers you can watch on a chest strap, a watch or your own pulse. This calculator estimates your maximum heart rate from your age — with the Tanaka formula (208 − 0.7 × age), the Gulati formula for women (206 − 0.88 × age) or the traditional 220 − age — or uses a maximum measured in an exercise test. It then builds five training zones as a percentage of your heart-rate reserve (the Karvonen method, which also uses your resting heart rate) or as a percentage of your maximum.
Alongside the zones you get the American Heart Association target zone (50–85% of maximum), the ACSM light, moderate and vigorous ranges, every formula side by side, and the number of beats to count in 30 seconds when you check your pulse by hand. Everything is calculated in your browser.
How to use it
- Enter your age and, if you know it, your resting heart rate — the AHA suggests checking it in the morning after a good night’s sleep, before you get out of bed: count your pulse for 30 seconds and multiply by 2.
- Choose how to estimate your maximum heart rate: Tanaka (the default), Gulati for women, 220 − age, or I know my maximum if you have had a supervised exercise test.
- Choose the zone method: % of heart-rate reserve (Karvonen), which needs your resting rate, or % of maximum.
- Read your five zones in beats per minute, the AHA and ACSM ranges and the 30-second pulse counts. Copy them or download a CSV for your training log.
Examples
Maximum 180 bpm (208 − 0.7 × 40) · reserve 120 bpm · Zone 2 (60–70% HRR): 132–144 bpm · ACSM moderate (40–59% HRR): 108–131 bpm · AHA target zone: 90–153 bpm
Maximum 175 bpm · AHA target zone (50–85%): 88–149 bpm — the same as the row for 45 years in the AHA’s chart
Maximum 162 bpm (206 − 0.88 × 50 = 162). Tanaka gives 173 and 220 − age gives 170, so her estimated maximum is 8–11 bpm lower.
The formulas
- Tanaka: HRmax = 208 − 0.7 × age. From a meta-analysis of 351 studies (18,712 people) and checked in a laboratory study of 514 healthy adults; the line did not differ between men and women or with activity level. The authors found that 220 − age underestimates the maximum in older adults.
- Gulati (women): HRmax = 206 − 0.88 × age, from exercise tests of 5,437 women without symptoms (mean age 52). The authors concluded that the traditional calculation overestimates the maximum for women.
- 220 − age: the traditional estimate, still used in the American Heart Association’s target heart rate chart.
- Karvonen (heart-rate reserve): target = resting + intensity × (maximum − resting). For a maximum of 180, a resting rate of 60 and 70%: 60 + 0.7 × 120 = 144 bpm.
- % of maximum: target = intensity × maximum. 70% of 180 = 126 bpm.
The maximum is rounded to a whole beat first; every target is then rounded to the nearest beat, so you can repeat the sums by hand.
The zones and target ranges
- Five zones split 50–100% into 10-point bands — the scheme heart-rate monitor makers such as Polar use: zone 1 very light (50–60%), zone 2 light (60–70%), zone 3 moderate (70–80%), zone 4 hard (80–90%) and zone 5 maximum (90–100%). Here they apply to whichever basis you choose, and the short note beside each zone paraphrases Polar’s description of it.
- American Heart Association: target heart rate is about 50–70% of maximum for moderate activity and 70–85% for vigorous activity. If you are just starting out, the AHA suggests aiming for the lower end (50%) and building up gradually.
- ACSM classes intensity as light at 30–39% of heart-rate reserve (57–63% of maximum), moderate at 40–59% (64–76%) and vigorous at 60–89% (77–95%), with very light below and near-maximal above.
The percentages of reserve and of maximum are not interchangeable: 60% of reserve is a higher heart rate than 60% of maximum, because the reserve starts from your resting rate.
Medicines, heart conditions and how sure the numbers are
The AHA notes that some drugs and medications affect heart rate, so you may have a lower maximum heart rate and target zone; if you have a heart condition or take medication, ask your health care professional what your heart rate should be. Beta blockers, for example, work by slowing down your heartbeat (NHS), so age-based zones do not apply to people taking them.
Every age formula describes an average: two healthy people of the same age can have quite different maximums. A maximum measured in a supervised exercise test is more personal than any formula. Effort also shows without numbers — on CDC’s talk test you can talk but not sing during moderate activity, and say only a few words before pausing for breath during vigorous activity.
Taking your pulse
The AHA’s method: find the pulse on the inside of your wrist, on the thumb side, with the tips of your first two fingers (not your thumb), press lightly, count for 30 seconds and multiply by 2. The tables show the 30-second count for each zone, so you can check without doing the sum mid-workout.
For most adults a resting heart rate between 60 and 100 bpm is normal, and an athlete or very active person may have one as low as 40 (AHA). Stress, anxiety, hormones, medication and activity all affect it.
Sources
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol 37(1):153-6
- Gulati M et al. Heart rate response to exercise stress testing in asymptomatic women: the St. James Women Take Heart Project. Circulation 122(2):130-7
- Karvonen MJ, Kentala E, Mustala O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 35(3):307-15
- Garber CE et al. ACSM position stand: quantity and quality of exercise… Med Sci Sports Exerc 43(7):1334-59 — the intensity classes repeated in ACSM’s Guidelines for Exercise Testing and Prescription, 11th ed. (Wolters Kluwer)
- American Heart Association. Target Heart Rates Chart
- NHS. Beta blockers · CDC. Measuring Physical Activity Intensity · Polar. Running heart rate zones: the basics
Limitations
- Age-based maximums are population averages; your own maximum may be well above or below the estimate.
- Not for people taking heart-rate-lowering medicines such as beta blockers, or with a heart condition — ask your doctor or cardiac rehabilitation team for your targets.
- Do not attempt an all-out effort to “find” your maximum on your own; a measured maximum should come from a supervised exercise test.
- Ages 15–90, resting rates of 30–120 bpm and measured maximums of 100–230 bpm are accepted. The formulas were developed in adults.
Privacy
Everything happens in your browser. What you enter or open here is not uploaded or stored by MySmartCoPilot.
Frequently asked questions
What is the Karvonen formula?
Target heart rate = resting heart rate + intensity × (maximum − resting). The difference between maximum and resting is your heart-rate reserve. With a maximum of 180 and a resting rate of 60, 70% intensity is 60 + 0.7 × 120 = 144 bpm. It was described by Karvonen, Kentala and Mustala.
What is zone 2 heart rate?
In the five-zone scheme it is 60–70% — of your maximum, or of your heart-rate reserve with the Karvonen method. For a 40-year-old with a resting rate of 60 and the Tanaka maximum of 180, that is 132–144 bpm by reserve or 108–126 bpm by maximum. It is the “light” zone of that scheme.
Should I use 220 − age or the Tanaka formula?
Tanaka et al. found 208 − 0.7 × age fits measured maximums across ages better and that 220 − age underestimates the maximum in older adults; the two agree at age 40 (180 bpm). The AHA’s own chart uses 220 − age. For women, the Gulati formula (206 − 0.88 × age) came from 5,437 women. The calculator shows all three so you can compare.
What is a normal resting heart rate?
For most adults, 60–100 beats per minute (American Heart Association). Very active people and athletes can be as low as 40. Check it in the morning before getting up.
I take beta blockers. Can I use these zones?
No. Beta blockers slow your heartbeat, and the AHA says medicines can lower your maximum heart rate and target zone. Ask your doctor or cardiac rehabilitation team for targets, or use perceived effort and the talk test instead.
Why is my zone in % of reserve higher than in % of max?
Because the reserve method starts from your resting rate: 60% of reserve = resting + 0.6 × (max − resting), which is always above 60% of max when your resting rate is above zero. The two methods are different scales, so stick with one.