Target Heart Rate Calculator

Your target heart rate is the ideal beats-per-minute (bpm) range to work at during exercise in order to achieve a specific training goal. Training within the right heart rate zone is one of the most reliable and science-backed ways to make sure every workout counts — whether you want to burn fat, build aerobic endurance, push lactate threshold, or maximize VO2 max.

Heart rate is a direct window into how hard your cardiovascular system is working. At rest, your heart ticks along at 60–100 bpm for most adults. During an all-out sprint, it can climb to 180–200 bpm or beyond. The space between those two extremes is where training happens, and knowing exactly which slice of that range to hit for your goals is what this target heart rate calculator is all about.

Unlike rough percentage-of-maximum-heart-rate rules, this calculator uses the Karvonen formula — which accounts for your individual resting heart rate — to give you personalized target zones that are far more precise. A trained athlete with a low resting HR of 45 bpm will have very different zone boundaries than a sedentary person of the same age with a resting HR of 80 bpm, even though they share the same maximum heart rate. The Karvonen method captures that difference.

Understanding your target heart rate zones also helps you avoid two of the most common training mistakes: working out too hard (leading to overtraining, injury, and burnout) and working out too easy (making slow or no progress). With clear zone boundaries, you can structure your weekly training to balance intensity and recovery like a professional athlete.

The Karvonen formula, developed by Finnish scientist Martti Karvonen in 1957, calculates target heart rate using heart rate reserve (HRR) — the difference between your maximum heart rate and your resting heart rate. This reserve represents the true working range of your cardiovascular system.

The formula first estimates your maximum heart rate using the widely used age-based equation: Max HR = 220 − Age. While individual variation exists, this equation is the standard in most fitness applications and clinical exercise testing protocols. It predicts, for example, that a 30-year-old has a max HR of 190 bpm and a 50-year-old has a max HR of 170 bpm.

From there, the heart rate reserve is computed by subtracting your resting heart rate from your maximum heart rate. A lower resting HR (a marker of good cardiovascular fitness) means a larger heart rate reserve — and therefore a larger spread of usable training zones. This is why fit individuals can tolerate higher absolute training intensities.

Finally, the Karvonen formula applies your chosen intensity percentage to this reserve and adds it back onto your resting heart rate. This produces a target zone that is calibrated to your individual fitness level, not just your age.

This calculator automatically computes all five standard training zones using the Karvonen formula. Each zone serves a distinct physiological purpose, and balancing time across zones is the foundation of effective periodized training.

Most endurance coaches recommend that 70–80% of total weekly training volume fall in the Recovery and Aerobic zones (Zones 1–2). The remaining 20–30% is reserved for higher-intensity work in the Tempo, Threshold, and VO2 Max zones. This polarized or pyramidal distribution builds a large aerobic base while still providing the high-intensity stimulus needed for performance improvements.

Your resting heart rate (RHR) is the single most important personal variable in the Karvonen formula. A difference of just 10 bpm in RHR can shift your training zones by 5–8 bpm — enough to make the difference between training in the right zone or the wrong one.

The most accurate way to measure RHR is first thing in the morning, before you get out of bed. After a full night of sleep and before the stimulation of standing, moving, eating, or caffeine, your heart rate is at its lowest point. Lie still for a minute after waking, then count your pulse for a full 60 seconds (or 30 seconds and double). Do this on three consecutive mornings and average the readings for best accuracy.

You can measure your pulse at the radial artery (inside of your wrist, below the thumb) or the carotid artery (side of your neck). Many smartwatches and fitness trackers display RHR automatically after a night of monitoring.

A typical resting heart rate for adults is 60–80 bpm. Well-trained endurance athletes may have resting HRs of 40–55 bpm. A consistently elevated RHR (above your personal baseline) can signal incomplete recovery, illness, or overtraining — making it a useful daily health metric beyond just training zone calculation.

Avoid measuring your resting heart rate after physical activity, stress, caffeine consumption, or dehydration, as all of these can artificially elevate the reading. An accurate RHR measurement is the foundation of getting the most out of this target heart rate calculator.

Knowing your target heart rate zones is only useful if you apply them consistently in your workouts. Here is how to integrate zone-based training into common exercise types.

For long slow distance runs (LSDs), keep your heart rate in the Aerobic Zone (60–70%). This builds mitochondrial density, improves fat oxidation, and develops the aerobic base that underpins all endurance performance. Many runners make the mistake of running too fast on easy days, pushing into the Tempo Zone and accumulating fatigue without additional aerobic benefit.

For tempo runs and threshold workouts, target the Threshold Zone (80–90%). This is the intensity at which lactate begins to accumulate faster than it can be cleared — training just below this point raises the threshold, letting you race faster before accumulating fatigue. Classic tempo workouts are 20–40 minutes at a comfortably hard effort.

For interval training aimed at improving VO2 max, work at 90–100% of maximum heart rate in short bursts of 3–8 minutes with equal recovery periods. These sessions are demanding and should make up no more than 10–15% of weekly training volume.

During strength training and cross-training, use the Recovery and Aerobic zones to keep sessions metabolically productive without taxing the central nervous system. On dedicated recovery days, staying under 60% intensity promotes blood flow and muscle repair without adding to cumulative fatigue.

Using a heart rate monitor during workouts removes guesswork and keeps you accountable to your plan. Over time, you will notice your pace increasing at the same heart rate — a clear sign of improved cardiovascular fitness and a reason to recheck your resting HR and recalculate your zones.