Target Heart Rate Calculator
Estimate an adult exercise heart-rate range with Tanaka age-predicted maximum and the heart-rate-reserve method.
Content updated August 7, 2026
Age-predicted maximum heart rate has substantial individual error, and heart-rate zones may not match ventilatory thresholds. Medication such as beta blockers, illness, pregnancy, heat, altitude and heart conditions can change the response. Stop exercise for concerning symptoms and seek professional guidance for clinical use.
This calculator combines an age-predicted maximum heart rate with a measured resting heart rate. It then applies the selected percentages to heart-rate reserve to produce an estimated exercise range.
The maximum uses the Tanaka equation, 208 − 0.7 × age. Age equations have substantial individual error, so the result is a planning estimate for healthy adults rather than a measured maximum, clinical threshold or instruction to exercise at a particular intensity.
The Target Heart Rate formula
Estimated HRmax = 208 − 0.7A; HRR = HRmax − HRrest; Target = HRrest + intensity × HRRA is age in years, HRrest is measured resting beats per minute, and intensity is the entered percentage divided by 100.
Worked example
At age 40 with a resting rate of 60 bpm, estimated maximum is 180 bpm and reserve is 120 bpm. Applying 50–70% HRR gives 120–144 bpm.
Assumptions, rounding, and limitations
Assumptions
- The user is an adult and the Tanaka healthy-adult population equation is being used only as an estimate.
- Resting heart rate is a calm measured value and the lower percentage is below the upper percentage.
- Selected intensities are mathematical percentages of estimated heart-rate reserve, not prescribed zones.
Rounding: The engine retains full precision. The main target range is rounded to the nearest whole beat per minute; supporting values show one decimal place.
Limitations
- Age-predicted maximum heart rate has wide individual error and does not measure a person's actual maximum.
- Heart-rate-reserve percentages may not match ventilatory thresholds or a clinically appropriate intensity.
- Medication, disease, pregnancy and environment can alter response; the calculator is not medical advice.
Sources
- Age-predicted maximal heart rate revisited — PubMed / Journal of the American College of Cardiology
- Heart rate reserve is equivalent to percentage VO2 reserve, not to percentage VO2max — PubMed / Medicine and Science in Sports and Exercise
- Measured maximal heart rates compared to commonly used age-based prediction equations — PubMed / American Journal of Human Biology
How heart-rate reserve changes the range
Heart-rate reserve is estimated maximum minus resting heart rate. For each boundary, the calculator multiplies reserve by the chosen intensity fraction and adds resting heart rate back.
Because resting heart rate is included, two people of the same age can receive different numerical ranges. A calm, repeatable resting measurement is more useful than a single noisy wearable reading.
A zone is not a physiological threshold
Predicted heart-rate zones do not necessarily match an individual's ventilatory or lactate thresholds. Research also shows wide individual spread around age-predicted maximum heart rates.
Beta blockers and other medications, heart conditions, illness, pregnancy, hydration, heat and altitude can materially change the response. Clinical exercise targets should come from appropriate assessment and a qualified professional.
Frequently asked questions
▶What maximum-heart-rate equation is used?
The calculator uses the Tanaka equation: estimated maximum heart rate = 208 − 0.7 × age.
▶What is heart-rate reserve?
It is the difference between estimated maximum and measured resting heart rate. The selected percentage is applied to that difference before resting heart rate is added back.
▶Are predicted target heart rates exact?
No. Age-predicted maximum heart rate has substantial individual error, and formula zones may not match measured physiological thresholds.
▶Can I use this while taking a beta blocker?
Medication can change heart-rate response, and research in beta-blocked patients shows formula limitations. Ask a qualified clinician for an appropriate exercise target.
▶How should I measure resting heart rate?
Use a calm resting measurement under repeatable conditions. Recheck unexpected values and do not rely on one noisy wearable reading for clinical decisions.
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Open calculator →Disclaimer: Target Heart Rate Calculator results are estimates for general information and education only, and are not financial, tax, legal or medical advice. Verify important decisions with a qualified professional.