Target Heart Rate Calculator
Target Heart Rate Calculator
The Target Heart Rate Calculator helps you determine your optimal heart rate zones for exercise using the Karvonen formula, which takes into account both your age and your resting heart rate. Training at the right heart rate intensity is one of the most effective ways to improve cardiovascular fitness, burn calories efficiently, and avoid overtraining or undertraining.
Heart rate is a direct measure of how hard your heart is working to supply oxygen to your muscles during exercise. The moderate zone (50 to 70 percent of your maximum heart rate) primarily improves aerobic endurance and fat burning. The vigorous zone (70 to 85 percent) improves anaerobic threshold and cardiovascular performance. The near-maximal zone (85 to 100 percent) develops speed and power.
The simplest way to estimate maximum heart rate is the formula 220 minus your age. The Karvonen formula improves on this by incorporating your resting heart rate, which accounts for individual differences in cardiovascular fitness. A person with a lower resting heart rate will have a wider target zone, reflecting greater cardiovascular efficiency.
Training in the correct heart rate zone is essential for achieving specific fitness outcomes. Zone 2 training, for example, improves mitochondrial density and fat oxidation, making it the foundation of endurance training for athletes across many sports. Zone 4 and Zone 5 intervals push the anaerobic threshold and improve VO2 max, but they require adequate recovery between sessions. Understanding which zone corresponds to your workout goal allows you to train more efficiently and avoid wasting time at intensities that do not align with your objectives.
The Karvonen formula is particularly valuable because it accounts for individual fitness level through resting heart rate. A well-trained athlete may have a resting heart rate of 40 bpm, while a sedentary individual might have one of 80 bpm. The standard 220-minus-age formula would give both people the same maximum heart rate estimate, but the Karvonen formula produces different target zones because it accounts for the heart rate reserve. This makes the calculator more personalized and accurate across different fitness levels.
Using the Target Heart Rate Calculator is simple:
- Enter your age in years to estimate your maximum heart rate using the formula 220 minus age.
- Enter your resting heart rate (RHR) in beats per minute. Measure it first thing in the morning before getting out of bed. Normal RHR for adults ranges from 60 to 100 bpm.
- Select your goal training zone: moderate (50-70%), vigorous (70-85%), or zone maximum (85-100%). You can also choose to see all zones.
- Click Calculate to see your maximum heart rate, heart rate reserve, target range in bpm, and perceived exertion level.
The results show your maximum heart rate, heart rate reserve, and target heart rate range for your selected intensity zone. You will also see the corresponding rating of perceived exertion, which helps you cross-check the number with how the workout actually feels. Use the target range as a guide during exercise by checking your heart rate periodically on a monitor or smartwatch. For steady-state cardio like jogging or cycling, aim to stay in the middle of your target zone. For interval training, let your heart rate drop to the lower end during recovery periods and rise into the upper end during work intervals.
The calculator uses two formulas. The first estimates maximum heart rate:
For example, a 30-year-old with a resting heart rate of 65 bpm training at 70 percent intensity: Maximum HR = 190 bpm, HRR = 125 bpm, Target HR = (125 x 0.70) + 65 = 152.5 bpm. For a 70 to 85 percent range, the target zone would be 152 to 171 bpm.
The five standard zones are: Zone 1 (50-60%, very light, warm-up and recovery), Zone 2 (60-70%, light, fat burning and aerobic endurance), Zone 3 (70-80%, moderate, improves cardiovascular efficiency), Zone 4 (80-90%, hard, increases lactate threshold), and Zone 5 (90-100%, maximum, develops explosive power).
| Zone | Intensity | Benefit |
|---|---|---|
| Zone 1 | 50-60% | Very light, warm-up and recovery |
| Zone 2 | 60-70% | Light, fat burning and aerobic endurance |
| Zone 3 | 70-80% | Moderate, improves cardiovascular efficiency |
| Zone 4 | 80-90% | Hard, increases lactate threshold and speed |
| Zone 5 | 90-100% | Maximum, develops explosive power and speed |
The 220-minus-age formula for maximum heart rate is a population estimate with a standard deviation of approximately 10 to 12 beats per minute. This means up to a third of the population may have a true maximum heart rate differing from the estimate by 10 or more beats.
The Karvonen formula assumes a linear relationship between heart rate and exercise intensity, which is a reasonable approximation but not perfectly accurate at very high or very low intensities. The calculator does not account for medications that affect heart rate, such as beta-blockers.
Heart rate can be influenced by dehydration, heat, caffeine, stress, illness, and fatigue. Use the calculator as a guideline and adjust based on how you feel.
Another factor the calculator cannot account for is how that special someone might make your heart race. For more information on matters of the heart that fall outside cardiovascular training zones, check the Love Calculator.
The linear heart rate to intensity relationship assumed by the Karvonen formula is a useful approximation but not universally accurate. At very high intensities near VO2 max, heart rate can plateau while oxygen consumption continues to rise. At very low intensities, heart rate may be disproportionately affected by external factors like temperature or emotional state. Additionally, the formula does not account for the heart rate drift phenomenon, where heart rate gradually increases during prolonged exercise even at a constant workload due to fluid loss and cardiovascular strain.
Certain medical conditions and medications significantly affect heart rate response to exercise. Beta-blockers, calcium channel blockers, and some anti-anxiety medications lower both resting and exercise heart rates, making the standard formulas inaccurate. Individuals with cardiac conditions, atrial fibrillation, or pacemakers should obtain personalized exercise prescriptions from a cardiologist rather than relying on general formulas. Always consult a healthcare provider before starting a new exercise program, particularly if you have known cardiovascular risk factors or symptoms.
Measure RHR Accurately
Take your resting heart rate first thing in the morning after a good night's sleep. Do this for three consecutive mornings and use the average.
Use a Heart Rate Monitor
Chest strap monitors are more accurate than wrist-based optical sensors, especially during high-intensity intervals or weight training.
Focus on Zones 2 and 3
Spend most training time in zones 2 and 3. Zone 2 builds aerobic base and fat metabolism. High-intensity work in zones 4 and 5 should be no more than 20 percent of total training volume.
Re-calculate Periodically
As your fitness improves, your resting heart rate drops and your heart rate reserve increases. Re-calculate your zones every few months.
- How do I find my resting heart rate?
- Measure first thing in the morning before getting up. Average over 3 consecutive mornings.
- What is the difference between Karvonen and 220-minus-age?
- Standard method ignores fitness level. Karvonen factors in resting heart rate for personalized zones.
- Which zone for fat burning vs endurance?
- Fat burning: Zone 2 (50-60%). Endurance: Zone 3-4 (60-80%). Higher zones target anaerobic performance.
- Is it accurate for people on medications?
- No. Beta-blockers lower heart rate. Use RPE scale instead if on heart-altering medication.
- Should I use target zone for every workout?
- No. Use for steady-state cardio. HIIT, strength, and recovery fall outside this zone.
- Karvonen, M. J., Kentala, E., & Mustala, O. (1957). The effects of training on heart rate. Annales Medicinae Experimentalis et Biologiae Fenniae, 35(3), 307-315.
- American College of Sports Medicine. (2021). ACSM's Guidelines for Exercise Testing and Prescription (11th ed.). Wolters Kluwer.
- Tanaka, H., Monahan, K. D., & Seals, D. R. (2001). Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology, 37(1), 153-156.
- Swain, D. P., & Leutholtz, B. C. (1997). Heart rate reserve is equivalent to VO2 reserve. Medicine and Science in Sports and Exercise, 29(3), 410-414.
Last updated: May 12, 2026