Heart Rate Reserve (Karvonen) Target Calculator
Find your target training heart rate from age, resting heart rate and intensity using the Karvonen heart-rate-reserve method.
How to use this tool
- Enter your age to estimate maximum heart rate.
- Enter your resting heart rate in bpm.
- Select the training intensity.
- Read your target heart rate and heart-rate reserve.
The Karvonen heart-rate-reserve calculator gives a personalised training target heart rate from your age, resting heart rate and chosen intensity — more individual than a flat percent of max.
⚠ This tool is for general information and education only and is not medical advice. Consult a qualified healthcare professional before making health decisions.
Formula
Target HR = resting HR + intensity × (HRmax − resting HR)
where HRmax = 220 − age and (HRmax − resting HR) is the heart-rate reserve (HRR). Intensity is the fraction of that reserve, e.g. 0.70 for vigorous effort.
How it works
The Karvonen method sets training heart-rate targets using heart-rate reserve (HRR), the gap between your maximum and resting heart rates. Because it anchors to your own resting rate, it personalises intensity better than taking a flat percentage of maximum heart rate: a fitter person with a low resting pulse gets a different target than someone with a high one at the same percentage.
Maximum heart rate here is estimated as 220 − age, a convenient rule with a wide individual spread (often ±10–12 bpm); a measured maximum is more accurate if available. Heart-rate targets are also affected by medications such as beta-blockers, heat, and fatigue, so use the result as a guide.
This calculator is provided for general information and education only and is not medical advice. Clinical formulas are screening and estimation tools, not diagnoses, and they assume valid, correctly-measured inputs. Always consult a qualified clinician before making any decision about your health.
Worked example
Age 30, resting HR 60, vigorous intensity (70%)
- Maximum HR = 220 − 30 = 190 bpm
- Heart-rate reserve = 190 − 60 = 130 bpm
- 70% of reserve = 0.70 × 130 = 91 bpm
- Add resting HR: 60 + 91 = 151 bpm
Target heart rate = 151.00 bpm (reserve 130 bpm)
Common mistakes to avoid
- Using the 220-age HRmax estimate instead of a measured maximum, which can misplace training zones by 10-20 bpm for individuals whose true MHR deviates from the formula.
- Measuring resting heart rate after activity instead of first thing in the morning; an elevated resting HR compresses the calculated reserve and narrows all training zones.
- Selecting 70% intensity for every workout rather than varying intensity by goal; low-intensity recovery work (50-60%) and high-intensity intervals (80-90%) drive different adaptations.
Karvonen target HR for age 30, resting HR 60 (HRR 130)
| Intensity | Target HR (bpm) |
|---|---|
| Light (50%) | 125.00 |
| Moderate (60%) | 138.00 |
| Vigorous (70%) | 151.00 |
| Hard (80%) | 164.00 |
Key terms
- Heart-rate reserve (HRR)
- The difference between maximum and resting heart rate; the range over which training intensity is scaled in the Karvonen method.
- Karvonen formula
- Target HR = resting HR + intensity × HRR, a personalised way to set training heart-rate zones.
- Maximum heart rate (HRmax)
- The highest heart rate achievable, commonly estimated as 220 minus age.
- Resting heart rate
- Heart rate at complete rest, lower in fitter people, used as the baseline in the Karvonen method.
Frequently asked questions
- Why use heart-rate reserve instead of percent of max?
- HRR includes your resting heart rate, so it adjusts for fitness. Two people the same age but with different resting rates get different, more appropriate targets at the same intensity.
- How accurate is 220 minus age?
- It is a rough estimate of maximum heart rate with a spread of about 10–12 bpm between individuals. A measured maximum from a stress or field test is more accurate.
- Do beta-blockers affect the target?
- Yes. Beta-blockers and some other medications lower heart rate, so formula-based targets can overshoot what is achievable; targets should be individualised in that case.