What Is the Karvonen Formula?
The Karvonen formula is a practical way to calculate your target heart rate range for exercise. Instead of using only age, it uses your heart rate reserve (HRR), which is the difference between your maximum heart rate and resting heart rate. That makes it more personalized than basic methods.
In simple terms, this method helps you train at the right intensity for your goals, whether that goal is fat loss, endurance, active recovery, or performance improvement.
The Formula
The Karvonen target heart rate equation is:
Target HR = ((Max HR − Resting HR) × Intensity) + Resting HR
If you do not know your tested max heart rate, a common estimate is: Max HR = 220 − age.
Why This Method Works Better Than Simple Percent-of-Max
Two people with the same age can have very different resting heart rates. A person with a low resting heart rate usually has a different cardiovascular profile than someone with a higher one. The Karvonen method captures that difference.
- More personalized: Accounts for resting heart rate.
- Better training precision: Useful for structured workouts.
- Goal-based programming: Easy to match intensity zones to outcomes.
How to Use This Karvonen Formula Calculator
- Enter your age.
- Enter your resting heart rate (best measured in the morning before getting out of bed).
- Optionally enter your measured max heart rate (if blank, the calculator uses 220 − age).
- Set your desired intensity range, such as 60% to 80%.
- Click calculate to get your personalized target heart rate range in beats per minute (bpm).
Heart Rate Training Zones (Quick Guide)
Zone 1 (50–60%) – Recovery
Very light effort, ideal for warm-up, cool-down, and recovery sessions.
Zone 2 (60–70%) – Aerobic Base
Comfortable but purposeful pace. Great for endurance and long-duration cardio.
Zone 3 (70–80%) – Tempo
Moderate to hard effort where breathing becomes more noticeable.
Zone 4 (80–90%) – Threshold
Hard effort. Useful for improving lactate threshold and sustained performance.
Zone 5 (90–95%) – Near Max
Very hard interval-level effort for short bursts. Use carefully and recover well.
Example Calculation
Suppose you are 40 years old, resting HR is 62 bpm, and you want to train at 70% intensity:
- Estimated Max HR = 220 − 40 = 180
- HR Reserve = 180 − 62 = 118
- Target HR = (118 × 0.70) + 62 = 144.6 bpm
Your training target at 70% is approximately 145 bpm.
Tips for Better Accuracy
- Measure resting heart rate over several mornings and use the average.
- If possible, use a tested max heart rate from a graded exercise test.
- Use a reliable heart rate monitor for real-time workouts.
- Adjust zones if medication, stress, sleep, or heat affects your heart rate response.
Important Safety Note
Heart rate calculators are educational tools, not medical diagnosis systems. If you have cardiovascular disease, symptoms during exercise, or are taking heart-related medications, speak with a qualified healthcare professional before starting a new program.