How the heart rate zone calculator works
Two steps: first the maximum heart rate, then five ranges built from it.
HRmax = 208 − 0.7 × age
Tanaka and colleagues published the formula in 2001 after pooling 351 studies. The classic 220 minus age underestimates the maximum in older people and overestimates it in younger ones; Tanaka removes that tilt. If you measured your maximum in a test or at the end of a race, the calculator uses that number instead.
Zone HR = HRmax × share
Zone HR = HRrest + (HRmax − HRrest) × share
The Karvonen formula takes the shares from your heart rate reserve, the gap between maximum and resting heart rate, rather than from the maximum alone. That brings fitness into the result: a runner resting at 50 bpm gets higher zones than someone the same age resting at 75. Both methods use the same zone edges: 50, 60, 70, 80, 90 and 100%.
Example: age 30, resting heart rate 60. The formula puts the maximum at 187 bpm, so the reserve is 127. Zone 2 as a share of max comes out at 112–131 bpm; with Karvonen it is 136–149. The lower edges are 24 beats apart because 60% of reserve and 60% of max are different workloads. For runners with a low resting heart rate, Karvonen usually matches how the run feels.
The five heart rate zones for running
Percentages are shares of max heart rate or of heart rate reserve, depending on the method. Watches and apps name the zones differently, but the order is the same: the higher the zone, the shorter you can hold it.
Zone 1 · recovery · 50–60 %
Effort that helps you recover from harder work. Warm-ups, cool-downs and the jog the day after a hard session belong here. For beginners, brisk uphill walking often lands in this zone too.
Zone 2 · aerobic base · 60–70 %
Where most running miles go, for recreational and elite runners alike. Blood lactate barely rises, so you can keep going for an hour or more while the heart and muscles adapt to long work.
Zone 3 · steady · 70–80 %
Too hard to recover in, too easy to work your threshold. When nearly every run drifts here, fatigue builds faster than fitness. The zone still has a job: most recreational runners hold marathon pace here or near the edge of zone 4.
Zone 4 · threshold · 80–90 %
Tempo runs of 20–40 minutes and 5–10 minute repeats with short recoveries. You can speak a few words at a time. This work teaches you to hold a fast pace for longer and carries 10K and half marathon training.
Zone 5 · VO₂max · 90–100 %
Intervals of 2–5 minutes and the end of a race. Heart rate lags behind effort by a minute or two, so on short repeats pace or feel is the better guide.
Heart rate zones by age
Max heart rate from the Tanaka formula and the five zone ranges as shares of it. Use the table if you do not know your resting heart rate; if you do, the calculator above gives a closer answer with Karvonen.
| Age | HRmax | Zone 1 | Zone 2 | Zone 3 | Zone 4 | Zone 5 |
|---|---|---|---|---|---|---|
| 20 | 194 | 97–116 | 116–136 | 136–155 | 155–175 | 175–194 |
| 25 | 191 | 96–115 | 115–134 | 134–153 | 153–172 | 172–191 |
| 30 | 187 | 94–112 | 112–131 | 131–150 | 150–168 | 168–187 |
| 35 | 184 | 92–110 | 110–129 | 129–147 | 147–166 | 166–184 |
| 40 | 180 | 90–108 | 108–126 | 126–144 | 144–162 | 162–180 |
| 45 | 177 | 89–106 | 106–124 | 124–142 | 142–159 | 159–177 |
| 50 | 173 | 87–104 | 104–121 | 121–138 | 138–156 | 156–173 |
| 55 | 170 | 85–102 | 102–119 | 119–136 | 136–153 | 153–170 |
| 60 | 166 | 83–100 | 100–116 | 116–133 | 133–149 | 149–166 |
| 65 | 163 | 82–98 | 98–114 | 114–130 | 130–147 | 147–163 |
| 70 | 159 | 80–95 | 95–111 | 111–127 | 127–143 | 143–159 |
All values in beats per minute. Neighbouring zones share an edge, the same way sports watches count them.
Zone 2: what it is and how to find it
Zone 2 is the heart rate at which running stays easy: steady breathing and full sentences without gasps. Physiologists tie it to the first threshold, the workload below which blood lactate barely rises. Heart rate zones approximate that threshold; they do not measure it.
You can check the numbers on your next run. Settle at the top of zone 2 and say a long sentence out loud. If it comes out easily, the zone fits. If your breathing cuts the sentence short, your threshold is lower, so keep easy runs 5–10 beats below the calculated range. If the top of the zone feels like a walk, your real maximum is probably higher than the formula, and it is worth measuring.
Most training plans give about 80% of weekly running time to low intensity, zones 1 and 2.
More on zone 2 running: the talk test, cardiac drift and where the 80/20 rule comes from →
Limits of the formula
The Tanaka formula describes the average for people your age well, but for one person it can be off by about 10 beats either way. Two 30-year-olds with the same estimate of 187 might really top out at 177 and 197, which shifts their zones by almost a full zone. A measurement is more accurate: a graded test in a lab, or a field test such as a 5K race with a hard final 400 metres recorded on a chest strap.
Heart rate lags behind effort by a minute or two and drifts upward in heat, with dehydration and late in a long run. That is why short intervals are better paced by speed, and why an easy long run can creep into zone 3 without you speeding up.
Optical wrist sensors miss more often than chest straps, especially during intervals and in the cold.
Beta blockers and some other medicines lower heart rate, and formula-based zones do not apply to anyone taking them. With heart disease, high blood pressure or during pregnancy, talk to a doctor about zones and about any maximal test.
Frequently asked questions
How do I calculate my heart rate zones?
Take your maximum heart rate, either measured or from the Tanaka formula 208 − 0.7 × age, and multiply it by 0.5, 0.6, 0.7, 0.8 and 0.9 to get the edges of five zones. If you know your resting heart rate, the Karvonen method is more precise: apply the same shares to the reserve (max minus resting) and add the resting rate back. At age 30 with a resting rate of 60, Karvonen zone 2 is 136–149 bpm.
What is the Karvonen formula?
A way to set heart rate zones from your heart rate reserve: zone HR = resting + (max − resting) × share. The Finnish physiologist Martti Karvonen proposed it in 1957. Resting heart rate reflects fitness, so a trained runner gets higher Karvonen zones than a beginner of the same age.
What heart rate is zone 2?
As a share of maximum it is 60–70% of HRmax, which is 112–131 bpm at age 30 with the Tanaka formula. With Karvonen and a resting rate of 60 it is 136–149. The talk test settles which fits you: at the top of zone 2 you should still speak in full sentences.
How accurate is a max heart rate calculator?
The Tanaka formula gives the average for your age group, and an individual can differ from it by about 10 beats either way. If formula-based zones do not match how runs feel, measure your maximum in a test and enter it in the calculator; it replaces the formula.
Why is my heart rate above zone 2 on easy runs?
Common causes are heat, poor sleep, caffeine, illness and the slow rise in heart rate late in a long run. Another possibility is that the formula underestimates your maximum. If you can talk in full sentences at that heart rate, the run is easy, and the zones should be recalculated from a measured maximum. New runners often need walk breaks in the first weeks to stay in zone 2, and that is normal.