Heart-rate zone calculator: compare equation assumptions
Explore five illustrative heart-rate bands from an age-based maximum estimate. Choose the equation and whether the bands use maximum heart rate or heart-rate reserve.
Heart-Rate Zone Calculator
No single maximum heart-rate formula is correct for everyone. Compare the six most-used equations side by side, see how your zones shift, and read the assumptions behind each one. Grounded in the ACSM and Circulation evidence base.
Live comparison — every formula updates together.
There is no single maximum heart rate that applies to everyone. The classic 220 − age formula was never developed from original research — it emerged from a cluster of approximately 11 data sources and has no scientific merit for individual prediction, as documented in the Tanaka 2001 review. Tanaka's own meta-analysis of 351 studies and 18,712 participants produced 208 − 0.7 × age with a standard error of roughly 7 bpm; the ACSM now recommends the Tanaka formula over 220 − age. Gulati's formula, derived from 5,437 asymptomatic women, produced a lower peak HR for women — 206 − 0.88 × age — because the traditional male-based equation overestimates women's HRmax. Nes and colleagues, analysing 3,320 healthy adults in the HUNT Fitness Study, found 211 − 0.64 × age with a standard error of 10.8 bpm, and noted that older subjects and women often have higher HRmax than earlier formulas predicted. A 2020 validation study in the International Journal of Exercise Science compared nine equations against measured treadmill HRmax in a general population and found wide limits of agreement for all of them — meaning every formula carries meaningful error at the individual level. The heart-rate reserve method (Karvonen) uses both HRmax and resting HR, and because percentage of HRR is closely equivalent to percentage of VO₂ reserve (the difference between resting and maximal oxygen uptake), it produces zones that better reflect actual metabolic intensity than percentage of HRmax alone. The MAF 180 formula is not a maximum HR — it is a single aerobic ceiling designed to keep you below your lactate threshold, adjusted for health and training history. Use these numbers as a reference. A field test or graded exercise test gives a far more accurate HRmax. No calculator replaces listening to your body.
Select an equation and a basis
Enter an adult age in whole years. The Tanaka equation uses 208 − 0.7 × age; the traditional shortcut uses 220 − age. Percentage of maximum multiplies the estimate directly. Heart-rate reserve adds resting heart rate to a percentage of the difference between estimated maximum and resting rate. Enter a resting value only for that method.
A worked example
At age 30, Tanaka gives an estimated maximum of 187 bpm. A 50–60% band based on maximum is approximately 94–112 bpm after rounding. If resting heart rate is 60 bpm, the same percentage band using reserve is approximately 124–136 bpm. The methods answer different arithmetic questions, so their boundaries are not interchangeable.
What the five bands mean here
The table divides 50–100% into five ten-percentage-point bands. This is an illustrative display convention, not a validated individual zone test. Adjacent rounded endpoints can touch. Other training systems use different bands, names and testing methods. This tool does not label a band as universally safe or prescribe time in it.
Why actual responses vary
Age-based equations describe averages. Individual maximum heart rate can differ substantially, and medication, health conditions, temperature and measurement errors can affect observed heart rate. A wearable reading cannot make the equation precise. Ask a qualified professional about personal exercise limits when relevant.
Why is my resting value rejected?
The reserve calculation needs resting heart rate below the estimated maximum. The form also uses broad adult input bounds to catch common mistakes. Passing validation does not establish that a reading is healthy or that exercise at any displayed rate is appropriate.
Sources and related tools
Equation source: Tanaka, Monahan and Seals, Age-predicted maximal heart rate revisited (2001). WHO physical activity guidance provides public-health context. It does not validate an individual exercise plan. For time-and-distance arithmetic, use the running pace calculator.
Editorial information
Prepared with AI assistance for Everyday Wellness Planner. Last checked: 9 October 2026. No independent clinical review is claimed. Read our editorial policy and educational disclaimer. Calculator inputs remain in this browser tab; ordinary site logs and analytics are described in the privacy notice.
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