Heart Rate Zone Calculator
Enter your age and resting heart rate (and your measured max if you know it) for five training zones by the Karvonen heart-rate-reserve method, with the plain percent-of-max version for comparison.
Measure lying down first thing in the morning, before coffee.
Leave blank to use Tanaka: 208 − 0.7 × age = 184.
Max HR used
184 bpm
220 − age would give 185
Heart-rate reserve
124 bpm
max − resting
Zone 2 (aerobic)
134–146
where most easy miles belong
| Zone | % HRR | Heart rate | Feels like |
|---|---|---|---|
| Z1 · Recovery | 50–60% | 122–134 bpm | Very easy; full conversation |
| Z2 · Aerobic / endurance | 60–70% | 134–146 bpm | Easy; can talk in sentences |
| Z3 · Tempo | 70–80% | 146–159 bpm | Moderate; short phrases only |
| Z4 · Threshold | 80–90% | 159–171 bpm | Hard; a few words at a time |
| Z5 · VO2max | 90–100% | 171–184 bpm | Maximal; no talking |
Zones by age (Karvonen, resting HR 60)
Max HR from Tanaka. If your resting rate is lower, every zone shifts down a few beats; higher, up. Run your own numbers in the calculator.
| Age | Max (Tanaka) | 220 − age | Z1 | Z2 | Z3 | Z4 | Z5 |
|---|---|---|---|---|---|---|---|
| 20 | 194 | 200 | 127–140 | 140–154 | 154–167 | 167–181 | 181–194 |
| 25 | 191 | 195 | 125–138 | 138–151 | 151–164 | 164–177 | 177–191 |
| 30 | 187 | 190 | 124–136 | 136–149 | 149–162 | 162–174 | 174–187 |
| 35 | 184 | 185 | 122–134 | 134–146 | 146–159 | 159–171 | 171–184 |
| 40 | 180 | 180 | 120–132 | 132–144 | 144–156 | 156–168 | 168–180 |
| 45 | 177 | 175 | 118–130 | 130–142 | 142–153 | 153–165 | 165–177 |
| 50 | 173 | 170 | 117–128 | 128–139 | 139–150 | 150–162 | 162–173 |
| 55 | 170 | 165 | 115–126 | 126–137 | 137–148 | 148–159 | 159–170 |
| 60 | 166 | 160 | 113–124 | 124–134 | 134–145 | 145–155 | 155–166 |
| 65 | 163 | 155 | 111–122 | 122–132 | 132–142 | 142–152 | 152–163 |
| 70 | 159 | 150 | 110–119 | 119–129 | 129–139 | 139–149 | 149–159 |
What each zone trains
| Zone | % HRR | Adaptation | Share of training |
|---|---|---|---|
| Z1 · Recovery | 50–60% | Blood flow and recovery; warm-ups, cool-downs, the day after a race. | 5-10% |
| Z2 · Aerobic / endurance | 60–70% | Mitochondria, capillaries, fat metabolism -- the aerobic engine. Long runs and most easy days. | 65-75% |
| Z3 · Tempo | 70–80% | Some aerobic benefit at more fatigue than Z2; the 'grey zone' most runners spend too long in. | under 10% |
| Z4 · Threshold | 80–90% | Lactate threshold: raises the pace you can hold for an hour. Tempo runs and cruise intervals. | 10-15% |
| Z5 · VO2max | 90–100% | VO2max: 3-5 minute intervals. Very effective, very costly; once a week is plenty. | 5-10% |
Measuring instead of estimating
- Resting HR: lying still on waking, three mornings, take the lowest. A chest strap or a finger on the wrist for 60 seconds both work; a watch's overnight minimum is usually a little lower than a true resting value.
- Max HR: after a thorough warm-up, 3 × 3 minutes hard uphill with 2 minutes jog; the peak in the last rep is within a few beats of your max. A 5K race finish gives a similar number. Only do this if you are healthy and used to hard running.
- Then re-run the calculator with the measured max in the optional box. Zones built on a measured max are worth far more than any formula.
Frequently Asked Questions
What is my zone 2 heart rate?
With the Karvonen method, 60-70% of your heart-rate reserve added to your resting rate. A 40-year-old with a resting HR of 60: max ≈ 180 (Tanaka), reserve 120, zone 2 = 60 + 72 to 60 + 84 = 132-144 bpm. It should feel easy enough to hold a conversation. The calculator does this for your numbers.
Is 220 minus age accurate?
Not very. It was never derived from data on individuals, and the standard deviation around it is 10-12 bpm, so a third of people are more than 10 beats off. Tanaka's 208 − 0.7 × age fits large datasets better, especially over 40. Neither replaces a measured max from a hard uphill effort or a race finish.
Why use heart-rate reserve instead of percent of max?
Because resting heart rate varies a lot between people (40 to 80 bpm in healthy adults) and percent-of-max ignores it. Karvonen anchors zones between your actual resting and max, so 60% means the same effort for a fit runner resting at 45 and a beginner resting at 75. Percent-of-max zones are simpler and are what many watches default to; both are shown.
Why is my heart rate high on easy runs?
Heat, dehydration, caffeine, poor sleep, stress and the first 10 minutes of any run all push it up, as does cardiac drift on long runs. Optical wrist sensors also lock onto cadence and report 170 when you are at 140. If your zone-2 pace feels like a jog and you can talk, trust the talk test over the wrist.
How much training should be in zone 2?
Roughly 80% of weekly time for most endurance runners, with the rest in zones 4-5 and very little in zone 3. That '80/20' pattern is what elite endurance athletes across sports converge on, and it works for recreational runners as long as the 80% is genuinely easy.
These calculators use published exercise-science formulas and are for training guidance. They are estimates, not medical advice: if you have a heart condition or are starting exercise after a long break, talk to a doctor before training by heart rate or pace targets.