Karvonen Target Heart Rate Calculator
Calculate your target heart rate for any intensity using the Karvonen (heart rate reserve) method.
How to use this tool
- Enter age, resting heart rate and training intensity in the fields above.
- Results update instantly as you type — or click Calculate.
- Read your target heart rate and the full breakdown beneath it.
The Karvonen method calculates target heart rate using heart rate reserve (HRR = max HR − resting HR), giving a more personalised result than simple percentage of max. For education only — consult a physician before starting a new exercise programme.
Formula
Max heart rate (MHR) = 220 − age
Heart rate reserve (HRR) = MHR − resting heart rate (RHR)
Target heart rate (THR) = HRR × intensity% + RHR
How it works
The Karvonen method, also called the heart rate reserve (HRR) method, personalises training zones by accounting for the individual's resting heart rate, not just age. The heart rate reserve — the difference between maximum and resting heart rate — represents the usable cardiovascular range, and training intensity is expressed as a fraction of that reserve added back to the resting heart rate.
Maximum heart rate is estimated here using the simple Fox formula (220 − age); individual MHR can vary by ±10–15 bpm from this estimate, so measuring MHR during a maximal exercise test provides a more accurate result.
Worked example
Worked example
- A 30-year-old with a resting HR of 60 bpm wants to train at 70% intensity.
- MHR: 220 − 30 = 190 bpm.
- HRR: 190 − 60 = 130 bpm.
- Target HR: 130 × 0.70 + 60 = 91 + 60 = 151 bpm.
Target heart rate = 151 bpm; HRR = 130 bpm; MHR = 190 bpm
Key terms
- Heart rate reserve (HRR)
- The difference between maximum and resting heart rate; it represents the functional range over which the heart can increase output during exercise.
- Karvonen method
- A formula developed by Finnish physiologist Martti Karvonen that calculates training heart rate using the heart rate reserve rather than simply a percentage of maximum heart rate.
- Resting heart rate (RHR)
- Heart beats per minute measured at complete rest, ideally first thing in the morning before rising. Lower RHR generally indicates better cardiovascular fitness.
- Training intensity zone
- A target range of heart rate (often expressed as a percentage of maximum or reserve) designed to elicit specific physiological adaptations such as fat oxidation (lower zones) or cardiovascular improvement (higher zones).
- Fox formula
- The widely used age-based equation MHR = 220 − age; simple but population-averaged and subject to individual variation of ±10–15 bpm.
Frequently asked questions
- What is heart rate reserve?
- HRR = Maximum HR − Resting HR. It represents the range of heart rates available for exercise. A higher HRR (lower resting HR) generally indicates better cardiovascular fitness.
- How is this different from the simple percentage method?
- Simple method: THR = MHR × intensity%. Karvonen: THR = (MHR − RHR) × intensity% + RHR. Karvonen gives higher target HRs at the same percentage because it accounts for resting heart rate.