Target heart rate calculator
Five training zones from your heart rate reserve. Karvonen is the default because it accounts for your resting rate, which a flat percentage of maximum does not.
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Result
These are estimates from population-level equations, not a measurement of you and not medical advice. Individual results vary widely. Talk to a doctor or a registered dietitian before making significant changes to how you eat or train.
How this is calculated
Karvonen (heart rate reserve)default
target = ((HRmax − HRrest) × intensity) + HRrest
zones as a share of heart rate reserve:
very light 50–60% · light 60–70% · moderate 70–80%
hard 80–90% · maximum 90–100%
- Source
- Karvonen MJ, Kentala E, Mustala O., Annales Medicinae Experimentalis et Biologiae Fenniae 35(3), 1957, pp. 307–315. Zone bands as used in ACSM’s Guidelines for Exercise Testing and Prescription.
- Assumes
- That training intensity scales with the working range between rest and maximum.
- Accuracy
- More individualised than a flat percentage of maximum, because it responds to resting heart rate. Its accuracy still depends entirely on the maximum it is given.
Tanaka maximum heart rate
HRmax = 208 − 0.7 × age
- Source
- Tanaka H, Monahan KD, Seals DR., Journal of the American College of Cardiology 37(1), 2001, pp. 153–156.
- Assumes
- A linear decline in maximum heart rate with age across the population.
- Accuracy
- Derived from a meta-analysis of 351 studies covering 18,712 subjects. The better predictor of the two, particularly over 40, where "220 minus age" systematically under-predicts.
Fox maximum heart rate
HRmax = 220 − age
- Source
- Fox SM, Naughton JP, Haskell WL., Annals of Clinical Research 3(6), 1971, pp. 404–432.
- Assumes
- The same linear decline, with a steeper slope.
- Accuracy
- Never derived from a regression — Fox and colleagues presented it as an approximation drawn by eye from scattered data. It carries a standard deviation of roughly 10 to 12 bpm, so about a third of people sit more than 10 bpm from the prediction. Included because it is ubiquitous, not because it is good.
Which formula should you use
This page defaults to Karvonen (heart rate reserve). More individualised than a flat percentage of maximum, because it responds to resting heart rate. Its accuracy still depends entirely on the maximum it is given.
- Tanaka maximum heart rate — Derived from a meta-analysis of 351 studies covering 18,712 subjects. The better predictor of the two, particularly over 40, where "220 minus age" systematically under-predicts.
- Fox maximum heart rate — Never derived from a regression — Fox and colleagues presented it as an approximation drawn by eye from scattered data. It carries a standard deviation of roughly 10 to 12 bpm, so about a third of people sit more than 10 bpm from the prediction. Included because it is ubiquitous, not because it is good.
Target heart rate zones by age (Karvonen, resting 65 bpm)
Zones are computed from heart rate reserve using the Tanaka maximum, at a resting rate of 65 bpm. A different resting rate shifts every zone, which is exactly why the Karvonen method is preferred over a flat percentage of maximum.
| Age | Max HR | Very light | Light | Moderate | Hard | Maximum |
|---|---|---|---|---|---|---|
| 20 y | 194 | 130–142 | 142–155 | 155–168 | 168–181 | 181–194 |
| 30 y | 187 | 126–138 | 138–150 | 150–163 | 163–175 | 175–187 |
| 40 y | 180 | 123–134 | 134–146 | 146–157 | 157–169 | 169–180 |
| 50 y | 173 | 119–130 | 130–141 | 141–151 | 151–162 | 162–173 |
| 60 y | 166 | 116–126 | 126–136 | 136–146 | 146–156 | 156–166 |
| 70 y | 159 | 112–121 | 121–131 | 131–140 | 140–150 | 150–159 |
Questions
- Is "220 minus age" accurate?
- Not particularly. It was never derived from a regression — it was an approximation drawn by eye from scattered data in 1971, and it carries a standard deviation of 10 to 12 beats per minute. Tanaka came from an actual meta-analysis and predicts better, especially over 40.
- Why does Karvonen need my resting heart rate?
- Because it works from heart rate reserve, the range between rest and maximum, rather than from the maximum alone. A fit person resting at 50 and an unfit person resting at 80 need different target rates for the same relative effort, and the plain percentage method misses that entirely.
- How do I measure my resting heart rate?
- On waking, before getting out of bed, over a full minute. A wrist tracker averaged across several nights works too. Measuring after coffee or activity gives a figure that is not resting, and every zone shifts with it.
- The two equations gave the same answer for me. Is that right?
- If you are 40, yes. Tanaka and Fox cross at exactly age 40, where both give 180 bpm. Below 40 Fox reads higher; above 40 Tanaka does.
- Should I train to these zones exactly?
- They are a guide, not a prescription. Both maximum heart rate equations carry wide individual variation, so your real zones may sit several beats either side. Perceived effort is a useful cross-check: if a "moderate" zone feels hard, trust your body over the equation.