Heart Rate Zones Calculator
Enter your age and resting heart rate and this tool returns five heart-rate zones as bpm ranges, using the Tanaka age-predicted maximum and the Karvonen heart-rate-reserve method. This is what the published equations give for your inputs, not a training prescription.
Method: Tanaka HRmax & Karvonen HRR • Checked 24 Aug 2026Enter your details
| Zone | % HRR | Target HR |
|---|
How the zones are calculated
First, a maximum heart rate is estimated from your age using the Tanaka equation. If you enter a measured HRmax, that value is used instead. Then the five zones are built with the Karvonen heart-rate-reserve (HRR) method, which scales each intensity band between your resting heart rate and your HRmax rather than from zero.
- age
- your age in years, used only to estimate HRmax
- HRmax
- maximum heart rate in bpm — measured if provided, otherwise the Tanaka estimate
- HR_rest
- your resting heart rate in bpm
- HRR
- heart-rate reserve, the span between resting HR and HRmax
- intensity%
- the lower and upper percentages of HRR that define each zone
The maximum-heart-rate step uses Tanaka, Monahan & Seals' 2001 equation, which replaced the older 220 − age rule. The zone step uses the Karvonen heart-rate-reserve method. Both are widely published references; other zone conventions (percentage of HRmax, or lactate/ventilatory thresholds) draw the lines in different places, so zones from one method are not directly comparable with another.
Worked example: age 40, resting HR 60
The Tanaka estimate gives HRmax = 208 − 0.7 × 40 = 180 bpm, so the heart-rate reserve is
HRR = 180 − 60 = 120 bpm. Each zone target is then 60 + intensity% × 120:
- Z1 Recovery (50–60%):
60 + 0.50×120to60 + 0.60×120 = 120–132 bpm - Z2 Endurance (60–70%):
60 + 0.60×120to60 + 0.70×120 = 132–144 bpm - Z3 Tempo (70–80%):
60 + 0.70×120to60 + 0.80×120 = 144–156 bpm - Z4 Threshold (80–90%):
60 + 0.80×120to60 + 0.90×120 = 156–168 bpm - Z5 VO2max (90–100%):
60 + 0.90×120to60 + 1.00×120 = 168–180 bpm
The five heart-rate zones (reference)
The percentage bands are fixed by the method; only the bpm values change with your HRmax and resting heart rate. The worked example below is for age 40, resting HR 60 (HRmax 180, HRR 120).
| Zone | % HRR | Typical purpose | Example (age 40, rest 60) |
|---|---|---|---|
| Z1 Recovery | 50–60% | Very easy, active recovery | 120–132 bpm |
| Z2 Endurance | 60–70% | Aerobic base building | 132–144 bpm |
| Z3 Tempo | 70–80% | Sustained moderate effort | 144–156 bpm |
| Z4 Threshold | 80–90% | Hard, near threshold | 156–168 bpm |
| Z5 VO2max | 90–100% | Maximal intervals | 168–180 bpm |
Accuracy notes and limits
This shows what the published Tanaka and Karvonen equations give for the inputs you entered. Heart-rate figures from population equations can differ substantially from your own physiology: the Tanaka estimate carries a standard deviation of roughly 10 bpm between individuals of the same age, so a measured maximum is always preferred. This is an educational reference, not medical or coaching advice. Consult a qualified clinician or coach before changing how you train, and seek medical advice before starting a new programme. See our editorial policy.
Frequently asked questions
Why use Tanaka instead of 220 − age?
The older 220 − age rule was never derived from careful data and tends to overestimate maximum heart rate in older people. Tanaka, Monahan & Seals (2001) re-derived the relationship from a meta-analysis and give 208 − 0.7 × age, but it still carries about a 10 bpm individual standard deviation.
Should I enter a measured HRmax?
Yes, if you have one. A maximum measured in a proper test reflects your own physiology far better than any age formula, so when you enter it this tool uses it in place of the estimate.
Why do the zones depend on resting heart rate?
The Karvonen method scales intensity across the heart-rate reserve — the gap between resting and maximum — rather than as a flat percentage of maximum. A lower resting heart rate widens that reserve and shifts the zones.
Related tools and reading
FTP training zones calculator
Turn your Functional Threshold Power into the seven Coggan cycling power zones as watt ranges.
How age grading works in running
How age-based adjustments are derived, and why individual variation limits what they can tell you.
Sources
- Tanaka, H., Monahan, K. D. & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1), 153–156. DOI 10.1016/S0735-1097(00)01054-8 — the 208 − 0.7 × age equation, with an individual standard deviation of about 10 bpm.
- Karvonen, M. J., Kentala, E. & Mustala, O. (1957). The effects of training on heart rate: a longitudinal study. Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3), 307–315 — the heart-rate-reserve method.