Target heart rate calculator and training zones
Target heart rate calculator: enter your age and resting heart rate to see all five training zones by percentage of maximum heart rate and the Karvonen method, side by side.
Your target heart rate is the range of beats per minute that matches how hard you want a session to be. The calculator below takes your age and resting heart rate and works out the limits of all five training zones using two different methods, showing the difference between them side by side.
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Allowing for the margin of error, somewhere between —.why?
Five zones, with your numbers
| Zone | % | %HRmax | Karvonen |
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Which studies is this calculation based on?
- Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-156. PMID 11153730Meta-analysis of 351 studies + a laboratory validation with 514 people
- 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. PMID 13470504The original source of the heart rate reserve (HRR) method
- Robergs RA, Landwehr R. The surprising history of the "HRmax=220-age" equation. J Exerc Physiol Online. 2002;5(2):1-10.A review of where the 220 − age formula came from and how far it deviates
The zone percentages (50-60%, 60-70%, …) aren’t a universal standard; they’re the widely used five-zone scheme. Garmin, Polar and Coros can draw these limits slightly differently in their defaults — so it’s normal if the zone 2 on your watch doesn’t match the range here exactly.
Why does target heart rate give two different results?
With the percentage of maximum heart rate method, each zone is simply a percentage of your estimated maximum heart rate. It’s easy to calculate, needs just one input and it’s what most watches use. The Karvonen method also takes your resting heart rate into account: first it finds your heart rate reserve (maximum minus resting), applies the percentage to that and then adds your resting heart rate back on.
At the same percentages Karvonen usually comes out higher, and the gap isn’t small. For a 40-year-old with a resting heart rate of 60 and an estimated maximum of 180 (220 − age), zone 2 is 108-126 bpm with the first method and 132-144 bpm with Karvonen. That’s one reason you’ll find such different answers to the same question online — not everyone uses the same calculation.
Measuring your resting heart rate properly
The whole Karvonen result rests on this one number, so how you measure it matters. Take it as soon as you wake up, before you get out of bed, on several days in a row, and use the average. Measured later in the day, coffee, stress and standing up all push it higher — and a high resting heart rate shifts your target heart rate range up further than it should be.
If your watch measures from your wrist, you can use its resting heart rate figure as a guide too. But a single lowest value during sleep isn’t automatically the best figure for the Karvonen calculation; for comparable results, measure under the same conditions as far as possible, in the morning at rest. Bear in mind that optical wrist readings have their own limits.
How precise is the calculated target heart rate?
It’s a guide, because your maximum heart rate is estimated from your age. Your real figure can typically differ from that estimate by 10-12 beats; differences of 20 beats or more are possible too. That’s roughly as wide as zone 2 itself — so the estimate can put an effort in the wrong zone. That’s why the calculator also shows a range of possible deviation under the result; that range isn’t a guaranteed limit.
If you know your real maximum heart rate from a field or lab test, open the Adjust maximum heart rate section in the calculator and enter it; the estimate is switched off and the range becomes personal to you. The American Heart Association’s target heart rate chart is built on the same rough estimate too; most sources don’t spell out that limit.
Does target heart rate change from sport to sport?
The same effort doesn’t produce the same heart rate in every sport. Values on the bike often run a little lower than when running. On a rowing machine much of your body is working; how fast your heart rate climbs also depends on your technique and fitness. And in alpine skiing, with descents, lift rides and waiting in turn, holding a steady target heart rate isn’t realistic anyway.
So rather than applying one range to every sport, you’ll get better results by watching your own data. If you’d rather go by perceived effort than heart rate, the RPE scale is a practical alternative.
What are the zones for?
Zones give you a shared language for how hard a session is. The lower zones describe aerobic work you can keep up for a long time; the upper zones describe short, hard efforts. In endurance programmes most of the volume is spent in the lower zones — which is the whole idea behind the base training phase.
Why zone 2 in particular gets talked about so much, how to find it with the talk test without looking at your watch, and how it feels in different sports — we cover all of that in our Zone 2 guide.
How is it calculated?
The whole calculation runs in your browser, and no data is sent to a server. Two formulas are offered for maximum heart rate: the well-known 220 − age and 208 − 0.7 × age, which was derived from a much larger dataset. The second reflects the average better in older adults, but it doesn’t guarantee a more accurate estimate for every individual; at 60 there’s a 6-beat difference between the two. The Karvonen method is based on the original 1957 study. The full references for the studies used are in the drop-down section under the calculator, with links to their sources.