Heart Rate Calculator
Choose maximum-heart-rate percentages or Karvonen heart rate reserve. Maximum heart rate is estimated separately as 220 − age.
A QUICK WALKTHROUGH
How to use this tool
- Choose a method and enter a whole age from 10 to 100.
- For Karvonen, enter resting heart rate from 30 to 120 bpm, below the estimated maximum.
- Read the five rounded bands as calculation references, not personal exercise guidance.
Separate formulas
Estimated maximum = 220 − age. HRR = estimated maximum − resting heart rate. Karvonen target = resting heart rate + HRR × percentage. The age estimate is not the Karvonen reserve formula or a measured maximum.
Five broad calculation bands
Both modes show 50–60%, 60–70%, 70–80%, 80–90%, and 90–100%, rounded to whole bpm. Maximum mode uses a percentage of estimated maximum; Karvonen uses a percentage of HRR plus resting heart rate. These bands are not clinical zones or individualized exercise or medical advice. Input limits are not medical normal ranges.
Sources and limits
Karvonen et al. (1957), PMID 13470504, is the historical reserve-method source. The American Heart Association worksheet illustrates maximum minus resting heart rate and adding resting heart rate to a reserve percentage. Neither source validates these five bands or 220 − age for an individual. Fitness, medications and health conditions are not modeled.
GOOD TO KNOW
Common questions
Why do the two modes give different results?
Maximum mode multiplies the estimated maximum by the percentage. Karvonen first subtracts resting heart rate, applies the percentage, then adds resting heart rate back.
What inputs are accepted?
Whole ages 10–100; in reserve mode, finite resting heart rates 30–120 bpm below estimated maximum. Zero or negative HRR is rejected. These are calculator input limits, not health classifications.
Are these accurate personal training or clinical zones?
No. Both modes rely on a rough age-based maximum estimate. The bands are general calculation references and do not prescribe exercise, diagnose, or provide individual medical advice.