Karvonen Target Heart Rate Calculator
Use this calculator to estimate your ideal training heart rate zone using the Karvonen formula (Heart Rate Reserve method).
What Is the Karvonen Formula?
The Karvonen formula is a practical way to calculate personalized exercise intensity based on your resting heart rate and estimated maximum heart rate. Instead of only using a basic percentage of max heart rate, it uses your heart rate reserve (HRR), which gives a more individualized training target.
Formula:
Target Heart Rate = ((Max HR − Resting HR) × Intensity) + Resting HR
Why This Method Is Useful
- Accounts for your baseline fitness by using resting pulse.
- Produces more realistic training zones than flat % max HR rules.
- Works for beginners, general fitness, and endurance planning.
- Easy to recalculate as your resting heart rate improves over time.
How to Use This Calculator
1) Enter your age
Your age is used to estimate maximum heart rate if you do not provide a tested value.
2) Enter your resting heart rate
Resting heart rate is most accurate when measured after waking, before caffeine, and before movement. Count beats for 60 seconds (or use a reliable wearable).
3) Choose intensity range
Common ranges:
- 50–60%: very light activity and recovery
- 60–70%: aerobic base and steady endurance
- 70–80%: moderate to hard conditioning
- 80–90%: high-intensity intervals (advanced)
Example Calculation
Suppose you are 40 years old with a resting heart rate of 60 bpm, and you want a 60–75% target zone.
- Estimated max HR = 220 − 40 = 180
- Heart rate reserve = 180 − 60 = 120
- Lower target = (120 × 0.60) + 60 = 132 bpm
- Upper target = (120 × 0.75) + 60 = 150 bpm
Result: your target training zone is approximately 132–150 bpm.
Training Zone Guide
Zone 1: Recovery / Easy
Light effort, conversation is effortless. Great for active recovery and beginners building consistency.
Zone 2: Aerobic Base
Often called the “engine-building” zone. Supports fat oxidation, endurance, and long-term cardiovascular efficiency.
Zone 3: Tempo / Moderate
Useful for improving sustained pace. Breathing is deeper, but still controlled.
Zone 4: Threshold
Hard effort. Builds speed endurance and raises lactate threshold, usually in shorter blocks.
Zone 5: High Intensity
Very hard intervals for advanced training. Should be programmed carefully with full recovery.
Important Notes on Accuracy
- The popular 220 − age maximum heart rate formula is an estimate; individual variation can be significant.
- Stress, sleep, hydration, medications, heat, and caffeine can all affect heart rate readings.
- If precision matters for competition, consider lab testing or a supervised field test.
Safety Reminder
This calculator is for educational and fitness planning purposes only. If you have a cardiovascular condition, are returning after illness, or are unsure about exercise intensity, consult a qualified healthcare professional before starting a new program.