Heart Rate Zone Calculator
Work out your five heart-rate training zones in beats per minute from your age — using the classic 220 − age rule or the Tanaka formula, with an optional Karvonen method anchored to your resting heart rate.
Estimated max heart rate
185 bpm
- Zone 1 — Very light (50–60% max HR)
- 93–111 bpm
- Zone 2 — Light (60–70% max HR)
- 111–130 bpm
- Zone 3 — Moderate (70–80% max HR)
- 130–148 bpm
- Zone 4 — Hard (80–90% max HR)
- 148–167 bpm
- Zone 5 — Maximum (90–100% max HR)
- 167–185 bpm
Each zone is a percentage band of your estimated maximum heart rate, using the standard five-zone model (50–100% in 10% steps). Max heart rate is an age-based estimate — individual values vary by ±10 bpm or more.
How to use this calculator
Enter your age and pick a max heart rate formula — 220 − age is the familiar classic; 208 − 0.7 × age (Tanaka) is the better-validated research formula, especially past age 40. Then choose a zone method. "% of max heart rate" needs nothing else and gives the standard zone chart most sports watches show. "Heart-rate reserve (Karvonen)" also uses your resting heart rate — measured before getting out of bed — and anchors the zones to it, which personalises the bands to your fitness level. The result panel shows your estimated max and all five zones as bpm ranges.
How the calculation works
Your maximum heart rate is estimated from age: 220 − age (Fox, 1971) or 208 − 0.7 × age (Tanaka, 2001). The two agree exactly at age 40; Tanaka runs higher for older adults and lower for younger ones, and carried the stronger evidence in a meta-analysis of hundreds of studies. The five zones are the standard training bands in 10% steps from 50% to 100%. With the %-of-max method each band is a straight percentage of max heart rate. With the Karvonen method the percentages apply to your heart-rate reserve — max minus resting — and are added back on top of resting: target = resting + % × (max − resting). Because the reserve method credits a low resting heart rate, its zones sit higher on the bpm scale for the same percentage band. Either way these are estimates: true max heart rate varies between individuals of the same age by ±10 bpm or more.
Worked example
A 35-year-old using 220 − age has an estimated max of 185 bpm. The %-of-max zones are: Zone 1 (50–60%) 93–111 bpm, Zone 2 (60–70%) 111–130 bpm, Zone 3 (70–80%) 130–148 bpm, Zone 4 (80–90%) 148–167 bpm and Zone 5 (90–100%) 167–185 bpm. Switching to the Karvonen method with a resting heart rate of 60 bpm gives a heart-rate reserve of 185 − 60 = 125 bpm, and the same bands become: Zone 1 123–135, Zone 2 135–148, Zone 3 148–160, Zone 4 160–173 and Zone 5 173–185 bpm — noticeably higher, because the reserve method anchors every zone to your resting rate.
Frequently asked questions
What are the five heart rate zones?
The standard model splits effort into five bands of your maximum heart rate: Zone 1 (50–60%) very light — warm-ups and recovery; Zone 2 (60–70%) light — conversational endurance pace where aerobic base is built; Zone 3 (70–80%) moderate — steady "comfortably hard" aerobic work; Zone 4 (80–90%) hard — threshold intervals you can hold for minutes, not hours; Zone 5 (90–100%) maximum — short sprints and VO2max efforts. Most sports watches (Garmin, Polar, and others) use these same 10% bands by default.
How accurate is the 220 − age formula?
It is a rough population average, not a personal measurement. The 220 − age rule traces to Fox and colleagues in 1971 and was never fitted as a precise regression; measured max heart rates for people of the same age spread with a standard deviation around 10–12 bpm, so an individual can easily be 20 bpm off the formula. The Tanaka formula (208 − 0.7 × age), from a 2001 meta-analysis in the Journal of the American College of Cardiology, tracks measured values better on average — the two agree at age 40, but at 65 Tanaka gives 162 bpm versus 155 from the classic rule. If you have a measured max from a race finish or a lab test, use that instead.
What is the Karvonen (heart-rate reserve) method?
Karvonen and colleagues proposed in 1957 that training intensity should be set as a percentage of your heart-rate reserve — the gap between maximum and resting heart rate — rather than of maximum alone: target = resting + % × (max − resting). Because a fitter person typically has a lower resting heart rate and therefore a bigger reserve, the method personalises the zones beyond what age alone can do, and %HRR corresponds more closely to the percentage of oxygen-uptake reserve used in exercise-physiology guidelines. It needs an honest resting heart rate: measure for a minute before getting out of bed, several mornings running.
Why is so much training recommended in Zone 2?
Zone 2 is the intensity where the aerobic system does nearly all the work but the effort is light enough to sustain for long periods and recover from quickly. Endurance athletes typically spend the large majority of their weekly volume there — the popular 80/20 split — because it builds mitochondrial density, fat-burning capacity and cardiac stroke volume with far less fatigue than harder zones. A practical check: in Zone 2 you can hold a conversation in full sentences; if you can only manage short phrases, you have drifted into Zone 3.
Why are my watch's zones different from this calculator's?
Three common reasons. First, your watch may use a different max heart rate — many let you set a measured max, or estimate one from workout data rather than a formula. Second, some default to heart-rate-reserve zones (Garmin offers %HRR mode) while this calculator defaults to %-of-max, and the two put the same percentages at different bpm values. Third, a few platforms use different band boundaries — three-zone models or lactate-threshold-based zones — rather than the five 10% bands. Check which basis your watch uses in its settings; the arithmetic here will reproduce it once the basis and max match.
Can I use these zones if I take medication that affects heart rate?
Age-based formulas assume an unmedicated heart-rate response, so they can be badly wrong if you take beta-blockers or other rate-limiting medication — these can lower both resting and maximum heart rate by 20–30 bpm, which shifts every zone. The same caution applies to some heart conditions and to pregnancy. In those cases heart-rate targets should come from your doctor or from a supervised exercise test, not from a formula; perceived-effort scales are often recommended instead. This calculator is for general fitness information, not medical advice.