Heart Rate Zone Calculator
The heart rate zone calculator computes five training zones by the Karvonen formula — from recovery to maximal effort. Enter your age and resting heart rate to get your maximum heart rate, the fat-burning range and target pulses for workouts of different intensity. If you also enter your current pulse, the calculator shows which zone you are in right now. All calculations run on your device.
How to use the calculator
Fill in two required fields. Your age is needed to estimate the maximum heart rate as “220 minus age”. Measure your resting heart rate in the morning, still in bed, before getting up: place two fingers on your neck beside the larynx or on the inside of your wrist, count beats for 30 seconds and multiply by 2. Averaging three mornings in a row is best. The third field — your pulse right now — can stay at zero, then the calculator shows only the zones. If you enter your pulse during or right after a workout, a verdict “you are in zone N” appears.
The five heart rate zones
The zones are counted from the heart rate reserve — the difference between the maximum heart rate and the resting heart rate. Each zone matches a training goal:
| Zone | Name | Heart rate reserve | Goal |
|---|---|---|---|
| 1 | Recovery | 50–60% | Very easy effort: warm-up, recovery, easy walking |
| 2 | Fat burning | 60–70% | Main fat-burning zone; can be held for a long time |
| 3 | Aerobic | 70–80% | Builds endurance and cardiovascular fitness |
| 4 | Anaerobic | 80–90% | Speed and power; lactate builds up quickly |
| 5 | Maximal | 90–100% | Peak effort for very short intervals; trained only |
Karvonen vs “220 minus age”
The classic formula “220 minus age” gives only the maximum heart rate — with a spread of about ±10–12 beats for a given person. The Karvonen formula is more useful for training because it accounts for your individual fitness through the resting heart rate: zone pulse = resting pulse + (maximum pulse − resting pulse) × zone fraction. Example: age 30, resting heart rate 65. Maximum ≈ 190, reserve = 125. Fat-burning zone (60–70%): 65 + 125×0.6 = 140 … 65 + 125×0.7 = 153 beats per minute. If the resting heart rate were 80, the range would shift up to 146–157 — that is why a generic table “for everyone” often does not fit.
How to measure your resting heart rate
The best time is the morning, right after waking, before you get out of bed. Place your index and middle fingers on your neck beside the larynx (under the jaw) or on your wrist just below the thumb. Press lightly until you feel the pulse. Count beats for 30 seconds and multiply by 2 — this is more accurate than counting a full minute (the pulse may slow down meanwhile). Repeat on three mornings and take the average. Most adults have a resting heart rate of 60–80 bpm; trained people have a lower one, because the heart pumps blood more efficiently.
Limitations
The calculation is approximate. The formula “220 minus age” is an average: for some individuals the maximum heart rate differs by 10–15 beats either way, and it is affected by genetics, medication (for example, beta-blockers lower the pulse) and chronic conditions. The resting heart rate fluctuates with sleep, stress, caffeine and illness. Chest straps are more accurate than wrist bands and finger counting. If you have hypertension, cardiovascular disease, are pregnant, or have not trained for a long time — agree the training load with your doctor, and use the calculator as a starting point for a conversation, not as a prescription.
The calculation is for information only and is not a medical recommendation.
Frequently asked questions
Updated: Oct 28, 2026