Heart Rate Zone Calculator
Calculate your five heart rate training zones based on age and resting heart rate, so you can train at the right intensity for your goal.
How to use the heart rate zone calculator
- Enter your age.
- Enter your resting heart rate (ideally measured in the morning before getting up).
- The calculator shows your max heart rate and your five heart rate zones, with a recommended beat range for each.
How the heart rate zones are calculated
The calculator uses the Karvonen formula, which accounts for both max heart rate and resting heart rate for a more accurate result than using max heart rate alone:
Heart rate reserve (HRR) = Max heart rate − Resting heart rate
Zone heart rate = HRR × intensity % + Resting heart rate
The five zones represent different training intensities, from light warm-up to maximal effort. Zone 2 (fat burning) and zone 3 (fitness) are often used most for endurance training, while zones 4 and 5 are used for interval training and short, hard sessions.
The formula is a starting point, not a measurement
Maximum heart rate estimated from age is a statistical average, and the spread between individuals of the same age is large — deviations of ten to fifteen beats in either direction are entirely normal. Two people of the same age can therefore have real training zones noticeably shifted from each other, and from what the formula shows. The zones should be read as approximate bands, not sharp boundaries.
Daily form shifts them further. Sleep loss, heat, altitude, dehydration, illness and caffeine all affect heart rate at a given effort, so the same pace can produce ten beats more on a bad day. Many experienced athletes therefore steer by perceived exertion in combination with heart rate, and use a maximum actually measured in a hard test rather than an age-based estimate.
Frequently asked questions
Why does the calculator use resting heart rate in addition to age?
Resting heart rate says something about your individual fitness and heart capacity. The Karvonen formula uses heart rate reserve (max heart rate minus resting heart rate) for a more accurate result than formulas that only use age.
Which zone should I train in to lose weight?
Zone 2, often called the "fat-burning zone", is well suited for longer, easy sessions. Total calorie burn over time still matters more for weight loss than which zone you train in.
How do I measure my resting heart rate correctly?
Measure your pulse right after you wake up, while still lying still, over several days for a representative average.