Target Heart Rate
Personalized training heart rate using the Karvonen method.
Target heart rate
153 bpm
70% (Karvonen)
Max heart rate
190 bpm
Heart-rate reserve
125 bpm
AI Breakdown & Smart Takeaway
Plain-English insight on your numbers
Get a personalized explanation of what these results mean — and how to improve them.
How the Target Heart Rate works
The Target Heart Rate Calculator uses the scientifically validated Karvonen method to deliver a personalized cardio training zone based on your age, resting heart rate, and desired exercise intensity — giving you a far more precise target than generic age-based formulas alone.
At the heart of this calculator is the Karvonen formula, which factors in your Heart Rate Reserve (HRR) — the difference between your maximum heart rate and your resting heart rate. Unlike the simplified '220 minus age' shortcut that produces a single raw number, the Karvonen method scales your target zone relative to your actual cardiovascular fitness baseline. This means a well-trained athlete and a sedentary beginner of the same age will receive meaningfully different training targets, which is exactly what personalized cardio programming requires.
To use the calculator, you input your age (used to estimate maximum heart rate via the 220 − age formula, or you can enter a measured max HR if you have one), your resting heart rate (ideally measured first thing in the morning before getting out of bed), and your target intensity percentage or zone. The tool then computes your Heart Rate Reserve, multiplies it by your chosen intensity percentage, and adds your resting heart rate back in to produce your target heart rate in beats per minute. A low resting heart rate — a sign of good aerobic conditioning — will produce a higher absolute target zone for the same intensity percentage, correctly reflecting that a fitter heart can work harder.
Cardio training is most effective when structured around distinct heart rate zones, typically ranging from Zone 1 (50–60% intensity, active recovery) through Zone 5 (90–100%, maximal effort). The Karvonen method anchors each of these zones to your individual physiology rather than population averages, which is why it remains the preferred approach in exercise science and cardiac rehabilitation settings. For general fat burning and aerobic base building, most guidelines recommend working in the 60–80% intensity range; for improving VO2 max and cardiovascular performance, intervals in the 80–90% range are highly effective.
A common mistake is using an inaccurate resting heart rate, which skews every downstream calculation. Measure it over three consecutive mornings and average the results for reliability. Similarly, the 220 − age formula carries a standard deviation of roughly ±10–12 bpm, so if you have access to a laboratory or field-tested maximum heart rate, entering that value will make your zones significantly more accurate. Wearable devices that report real-time heart rate let you stay within your calculated zone during workouts, turning this calculator's output into a live coaching tool rather than just a number on a screen.
Formula
Target = Resting + (Max − Resting) × intensity [Karvonen]
Pro tips
- Measure your resting heart rate on three consecutive mornings before rising and use the average — a single rushed measurement can be 5–10 bpm too high and throw off your entire zone calculation.
- If you have a recent VO2 max or stress test result that includes your true maximum heart rate, enter that value instead of the age-estimated one to make every zone significantly more accurate.
- Use Zone 2 (60–70% intensity via Karvonen) for the majority of your weekly cardio volume — research consistently shows this builds aerobic base without excessive recovery demand, allowing higher training frequency.
- Rerun the calculator every 8–12 weeks or after a significant fitness change; as your resting heart rate drops with improved conditioning, your zones will shift upward and your old targets may become too conservative.
- Cross-reference your calculated zone with perceived exertion: at 70% Karvonen intensity you should be able to speak in short sentences but not hold a full conversation — if you can sing, push harder; if you cannot speak at all, back off.
Key terms
- Heart Rate Reserve (HRR)
- — The difference between your maximum heart rate and your resting heart rate, representing the functional range your heart can operate across during exercise.
- Karvonen Method
- — A formula for calculating target heart rate that uses Heart Rate Reserve to personalize training zones based on an individual's fitness level, not just their age.
- Resting Heart Rate (RHR)
- — The number of times your heart beats per minute while fully at rest, typically measured in the morning before physical activity; a lower value generally indicates better cardiovascular fitness.
- Maximum Heart Rate (MHR)
- — The highest number of beats per minute your heart can achieve during all-out exertion, commonly estimated as 220 minus your age or measured via a graded exercise test.
- Training Zone
- — A defined intensity band expressed as a percentage of maximum or reserve heart rate, each zone targeting different physiological adaptations such as fat metabolism, aerobic endurance, or peak power.
- Intensity Percentage
- — The proportion of your Heart Rate Reserve at which you choose to train, typically ranging from 50% for light activity to 95% for near-maximal interval efforts.
