UNDERSTAND THE METHOD
How to use this calculator
Choose an equation or enter a measured maximum. Add resting heart rate to calculate reserve-based ranges. Enter zero for resting heart rate to calculate percentages of maximum heart rate. The five intervals run from 50% to 100%.
What the result can tell you
Age equations estimate group averages and can differ substantially from an individual test. Medication, illness, and other factors can change your heart-rate response. These ranges do not establish that an intensity is safe for you. The Gulati equation comes from a study of women.
Common questions
When should I enter zero for resting heart rate?
Enter zero to calculate ranges as percentages of maximum heart rate. Enter a resting heart rate to calculate heart-rate-reserve ranges.
Do these zones show that an intensity is safe for me?
No. Age equations estimate group averages and can differ from an individual result. Medicines, illness, and other factors can change heart-rate response.
Sources & limitations
Sources checked September 12, 2026. These notes identify methods and assumptions. They have not received an independent clinical review.
- Tanaka and colleagues report an age-predicted maximum heart-rate equation.pubmed.ncbi.nlm.nih.gov
- Gulati and colleagues report a women-specific equation.pubmed.ncbi.nlm.nih.gov
- A comparison documents limitations of age-predicted maximum heart rate.pmc.ncbi.nlm.nih.gov