Calculator Cardio
Heart rate zones calculator
Training zones tell you how hard you're actually working. This uses the Karvonen method, which factors in your resting heart rate for zones tailored to your fitness — more accurate than a plain percentage of max.
| Zone | Effort | BPM |
|---|
By the numbers Context
What heart rate zones are and how they are set
Training by heart rate lets you steer effort rather than guess it. The zones are simply percentages of your maximum heart rate, and each band develops something different: the lower zones build endurance and fat-burning efficiency, while the higher zones push your ceiling for speed and power. This calculator maps your zones so you can match your workout to your goal.
The quick estimate of maximum heart rate is 220 minus your age, but it can be off by a fair margin for any individual. The Karvonen method used here refines the zones by factoring in your resting heart rate, which reflects your fitness — giving bands that fit you better than the age formula alone. Much aerobic training is best done in Zone 2, the conversational pace that builds a big aerobic base without excessive fatigue.
220 − age
the classic (rough) estimate of maximum heart rate
Fox
Zone 2
the ~60–70% band that builds your aerobic base
Training science
Sources: Fox/Haskell maximum-heart-rate estimate; Karvonen heart-rate-reserve method.
Frequently asked questions
What is a good heart rate for my age?
For training, what matters is your zones relative to your maximum, which is roughly 220 minus your age. A resting heart rate for adults typically sits between 60 and 100 bpm, with fitter people often lower. This calculator builds your zones from these.
What are the heart rate training zones?
There are usually five: Zone 1 (very light, ~50–60% of max), Zone 2 (light, ~60–70%), Zone 3 (moderate, ~70–80%), Zone 4 (hard, ~80–90%), and Zone 5 (maximum, ~90–100%). Each develops a different aspect of fitness.
What is zone 2 cardio?
Zone 2 is a comfortable, conversational effort at roughly 60–70% of your maximum heart rate. It builds your aerobic base and endurance efficiently, which is why so much endurance training is done there.
How are heart rate zones calculated?
They are percentages of your maximum heart rate. This calculator uses the Karvonen method, which factors in your resting heart rate to personalise the zones rather than relying on the age formula alone.
Is the 220-minus-age formula accurate?
It is a useful rough guide but can be off by 10–15 beats for a given person. For precise zones, a lab test or a maximum-effort field test is more accurate than any formula.