A heart rate zone calculator turns age and resting heart rate into five training ranges, in beats per minute, so a watch readout means something during a run or a ride. The number most people want is Zone 2: steady work you can still talk through, used to build an aerobic base. Generic “220 minus age” charts ignore how low your resting pulse is. A runner with a resting heart rate of 48 and a lifter with a resting heart rate of 72 should not share the same Zone 2 ceiling, even at the same age.
This calculator uses the Tanaka estimate of maximum heart rate and the Karvonen heart-rate reserve method, which is what the tool above applies when you enter a profile. It is a planning aid for healthy adults, not a clearance to start hard intervals, and not a substitute for a medically supervised test if you have chest pain, a known rhythm problem, or you are returning to exercise after illness. Count a true resting pulse for 60 seconds on waking, on two or three mornings, and average them before you trust the zones.
The Karvonen zone formula
Target HR = resting HR + (max HR − resting HR) × zone fraction
Heart-rate reserve: Karvonen, Kentala, and Mustala, Annales Medicinae Experimentalis et Biologiae Fenniae, 1957. Max heart rate here uses Tanaka, Monahan, and Seals, Journal of the American College of Cardiology, 2001: 208 − 0.7 × age. The older 220 − age estimate is shown in the notes for comparison only.
Heart-rate reserve (HRR) is max heart rate minus resting heart rate. A 35-year-old has a Tanaka max of 208 − 0.7 × 35 = 183.5, which rounds to 184. With a resting pulse of 60, HRR is 124. Zone 2 on this page is 60–70% of HRR, so the floor is 60 + 124 × 0.60 = 134 bpm and the ceiling is 60 + 124 × 0.70 = 147 bpm.
The five zones used above are 50–60% (Zone 1, easy recovery), 60–70% (Zone 2, aerobic base), 70–80% (Zone 3, tempo), 80–90% (Zone 4, threshold), and 90–100% (Zone 5, very hard). These percentages are of heart-rate reserve, not of max heart rate. A chart that says “Zone 2 is 60–70% of max” will print a lower band. Do not mix the two systems in one week of training.
220 − age is a rough population line from the 1970s and is noisy for individuals — often off by 10 beats or more. Tanaka’s 208 − 0.7 × age is a later fit to a wider adult sample and is what this tool uses. A laboratory max test, or the highest pulse you have actually recorded in a hard finish when you are healthy, beats both formulas. If you know a measured max, subtract age out of the story and set max heart rate to that number.
Worked examples
Example 1 — age 35, resting 60 bpm
- Tanaka max = 208 − 0.7 × 35 = 183.5, rounded to 184 bpm. The 220 − age estimate would be 185, almost the same at this age.
- Heart-rate reserve = 184 − 60 = 124 bpm.
- Zone 2 = 60 + 124 × 0.60 to 60 + 124 × 0.70 = 134 to 147 bpm.
- Zone 4 (80–90% HRR) = 159 to 172 bpm. That is the band for short hard repeats, not for a 45-minute easy run.
Example 2 — age 50, resting 52 bpm
- Tanaka max = 208 − 0.7 × 50 = 173 bpm. The 220 − age line would say 170.
- Heart-rate reserve = 173 − 52 = 121 bpm.
- Zone 2 = 52 + 121 × 0.60 to 52 + 121 × 0.70 = 125 to 137 bpm.
- A low resting pulse pulls every zone down. If this person trained at a generic “fat-burn” sticker of 140, they would already be above their Zone 2 ceiling and into tempo work.
Example 3 — age 28, resting 72 bpm
- Tanaka max = 208 − 0.7 × 28 = 188.4, rounded to 188 bpm.
- Heart-rate reserve = 188 − 72 = 116 bpm.
- Zone 2 = 72 + 116 × 0.60 to 72 + 116 × 0.70 = 142 to 153 bpm.
- Same sport, higher resting pulse, higher Zone 2 than example 2. Resting heart rate is why two training partners should not copy each other’s watch alerts.
How to use Zone 2 without turning every run into a tempo
Zone 2 is the 60–70% heart-rate-reserve band: a pace where you can speak in full sentences and you are not drenched in the first ten minutes. Most recreational runners drift into Zone 3 because Zone 2 feels “too easy” next to a group. The point of the zone is repeatable volume. Three or four sessions a week of 30 to 60 minutes, held inside the bpm range, beat one heroic session that spends half its time in Zone 4.
Wrist optical sensors lag on intervals and run high on hills. For the first two weeks, glance at the watch, then use the talk test as the tie-breaker. If you cannot finish a sentence, you are above Zone 2 regardless of the display. Heat, caffeine, poor sleep, and dehydration all raise heart rate at the same pace. On those days, slow down to the bpm ceiling instead of defending last week’s speed.
Lifters who add Zone 2 for recovery should put it on non-leg days or after lifting, not before a heavy squat. Twenty to forty minutes is enough to start. The meal side of the same week still matters: easy aerobic work does not require a huge calorie cut, and cutting too hard while adding sessions is how resting heart rate climbs and Zone 2 becomes miserable.
When the formula is the wrong tool
Beta blockers, some calcium-channel blockers, and several other drugs cap heart rate. Zones built from a healthy-adult formula will be unreachable and should not be chased. Pregnancy, anemia, thyroid disease, and recent viral illness also shift pulse independent of fitness. If resting heart rate is up more than about 7 beats from your own baseline for several mornings, skip the hard zones and keep any work in Zone 1 until it settles.
A max heart rate formula is not a stress test. Chest pain, unexplained shortness of breath, fainting, or a known arrhythmia is a reason to stop and get medical advice, not to recalculate Zone 5. Implanted devices and atrial fibrillation make pulse-based zones unreliable; use perceived effort or a clinician’s plan instead.
Frequently asked questions
What heart rate is Zone 2?
On the Karvonen scale this calculator uses, Zone 2 is 60 to 70 percent of heart-rate reserve, not 60 to 70 percent of max heart rate. For a 35-year-old with a resting pulse of 60 and a Tanaka max of 184, that is about 134 to 147 bpm. Your number moves with both age and resting heart rate. If a blog says Zone 2 is 60–70% of max, it is using a different system and the beats will not match this page.
Should I use 220 minus age or the Tanaka formula?
This tool uses Tanaka: 208 minus 0.7 times age. At age 40 that is 180, while 220 − 40 is 180 as well; the two lines diverge more at the young and older ends. Both are estimates. A measured maximum — the highest pulse in a hard, healthy finish, or a lab test — is better than either equation. Do not take a max test if you have cardiac symptoms or your clinician has told you to avoid all-out efforts.
How do I measure resting heart rate for the calculator?
Lie still for a minute after waking, before coffee and before looking at the phone. Count the pulse at the wrist or neck for a full 60 seconds, or use a chest strap if you already trust it. Average three mornings. A single night after alcohol or a hard session will print a high resting rate and shrink every zone. Wrist watches are acceptable if you compare them once against a manual count.
Why is my watch Zone 2 different from this calculator?
Watches pick their own max-heart-rate equation, their own zone percentages, and sometimes a max they inferred from a single hard run. Some use percent of max; this page uses percent of heart-rate reserve. Write down the bpm range from the examples above and set the watch zones to those beats if the watch allows custom zones. The bpm number is what you train to. The zone label is just a name.
Is the fat-burn zone a real thing?
At easier intensities a larger share of energy comes from fat, and at harder intensities a larger share comes from carbohydrate. Total fat burned in a session is intensity times time, so a long Zone 2 session can burn more fat than a short sprint even though each minute of the sprint is “harder.” There is no magic bpm that melts fat by itself. Fat loss still depends on the week’s calorie balance. Use the TDEE calculator for that, and use zones to make the cardio repeatable.
How long should a Zone 2 session be?
Thirty minutes is a useful minimum if you are starting. Forty-five to seventy minutes, two to four times a week, is a common base for people who already lift. Heart rate should sit inside the Zone 2 band for most of the session, not just the average. A session that spikes to Zone 4 on every hill and dips in between is not a Zone 2 session even if the average looks perfect.
Do heart rate zones change if I get fitter?
Resting heart rate often falls as aerobic fitness improves, which lowers every Karvonen zone even if max heart rate stays put. Recalculate when your morning pulse has dropped about 5 beats and stayed there for a week. Max heart rate itself declines slowly with age and does not rise just because you trained. Pace at a given bpm should get faster. That faster pace, not a higher zone, is the fitness gain.
Can I use this heart rate zone calculator for cycling and rowing?
Yes. The bpm targets do not care about the machine. Cycling often shows a slightly lower heart rate than running at the same perceived effort because you are seated and not absorbing impact. Stay inside the bpm band rather than copying a running pace. On a rower, grip fatigue and heat push heart rate up; slow the stroke rate to hold Zone 2 instead of forcing power.
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