Target Heart Rate Calculator (Karvonen)
Find the heart-rate zones for moderate and vigorous exercise.
Your numbers
Your results
Target Heart Rate Calculator (Karvonen) by TheCalcTools
How the Target Heart Rate Calculator (Karvonen) works
Enter your age, resting heart rate and choose a formula for maximum heart rate.
Heart rate reserve is the maximum minus the resting rate.
Each zone is a percentage of that reserve added to the resting rate.
The formula
Worked example
Using the default values shown in the calculator:
| Age (years) | 40 |
|---|---|
| Resting heart rate (bpm) | 60 |
| Max HR formula | 220 − age |
- HRmax = 220 − 40 = 180; reserve = 180 − 60 = 120.
- Moderate zone: 60 + 0.5 × 120 = 120 to 60 + 0.7 × 120 = 144 bpm.
- Vigorous zone: 144 to 162 bpm.
Result:
| Estimated max heart rate (bpm) | 180 |
|---|---|
| Moderate zone, low (50%) | 120 |
| Moderate zone, high (70%) | 144 |
| Vigorous zone, low (70%) | 144 |
| Vigorous zone, high (85%) | 162 |
Frequently asked questions
What counts as moderate exercise?
Public health guidance describes it as 50–70% of maximum effort, where you can talk but not sing.
How do I measure resting heart rate?
Count your pulse for 30 seconds on waking, before getting out of bed, and double it. Average over a few mornings.
Sources and further reading
Related calculators
More in Health & Fitness · All calculators
This calculator gives general estimates for information and education. It is not medical advice and does not diagnose anything. Talk to a qualified health professional about your own situation. See our disclaimer.