Heart Rate Calculator
Calculate your maximum heart rate and training zones based on your age and fitness level.
* Formulas are statistical estimates. Your actual maximum heart rate can only be measured with a controlled exercise test. Consult a doctor before starting a high-intensity training programme.
How is maximum heart rate calculated?
There are two main formulas for estimating MHR:
The Tanaka formula, published in the Journal of the American College of Cardiology, is more accurate for adults because it accounts for the fact that MHR does not decline linearly with age.
The 5 training zones
| Zone | % MHR | Intensity | Main benefit |
|---|---|---|---|
| Zone 1 | 50–60% | Very light | Active recovery, warm-up |
| Zone 2 | 60–70% | Light | Fat burning, base endurance |
| Zone 3 | 70–80% | Moderate | Aerobic capacity, performance |
| Zone 4 | 80–90% | High | Anaerobic threshold, speed |
| Zone 5 | 90–100% | Maximum | Power, peak speed |
What is the Karvonen formula?
The Karvonen formula uses heart rate reserve (the difference between MHR and resting HR) to calculate more personalised zones:
It is more accurate than using a percentage of MHR alone because it takes your current cardiovascular fitness into account. A low resting HR indicates better physical condition.
Frequently asked questions about heart rate
How is maximum heart rate calculated?
The classic formula is MHR = 220 − age. The more accurate Tanaka formula is MHR = 208 − (0.7 × age). Only a real maximal exercise test can give you your exact MHR.
What are training zones?
HR ranges corresponding to different intensities: Zone 1 (recovery), Zone 2 (fat burn), Zone 3 (aerobic), Zone 4 (anaerobic) and Zone 5 (maximum). Training in each zone produces different adaptations.
What is the Karvonen formula?
It calculates zones using heart rate reserve (MHR − resting HR), making it more accurate. The formula is: Target HR = Resting HR + (% intensity × (MHR − Resting HR)).
What is a normal resting heart rate?
Between 60 and 100 bpm for a healthy adult. Well-trained athletes may have 40–50 bpm, indicating greater cardiac efficiency. Measure it when you wake up, before getting up.