What is your target heart rate?
Your target heart rate is the range, in beats per minute, that corresponds to a chosen exercise intensity. Training within a specific range lets you match your effort to your goal — easier zones build endurance and burn fat, harder zones build speed and fitness — instead of guessing whether you're working hard enough.
The Karvonen formula
The Karvonen method calculates target heart rate from your heart-rate reserve (HRR), which is the difference between your maximum and resting heart rates. Because it accounts for your resting heart rate, it personalises the result to your fitness level rather than using a one-size-fits-all percentage of max.
- Maximum heart rate ≈ 208 − 0.7 × age (Tanaka), or 206 − 0.88 × age for women (Gulati)
- Heart-rate reserve (HRR) = maximum HR − resting HR
- Target HR = resting HR + (intensity % × HRR)
Worked example
Take a 30-year-old woman with a resting heart rate of 60 bpm. Her estimated max (Gulati) is 206 − 0.88 × 30 ≈ 180 bpm, so her heart-rate reserve is 180 − 60 = 120 bpm. For a 60% intensity, her target is 60 + 0.6 × 120 = 132 bpm. For 80%, it's 60 + 0.8 × 120 = 156 bpm.
Why use resting heart rate?
Simple methods like '70% of 220 − age' ignore the fact that two people of the same age can have very different fitness. A well-trained athlete might have a resting heart rate of 45 bpm while someone unfit sits at 75. The Karvonen formula uses your resting heart rate to anchor the zones to your own cardiovascular system, producing target ranges that better reflect how hard you're actually working.
Target heart rate by intensity
Health authorities generally split exercise into moderate and vigorous intensity. The table below shows how those map to your heart-rate reserve, alongside the five more granular training zones the calculator produces.
| Intensity | % of heart-rate reserve | Use it for |
|---|---|---|
| Moderate | 50–70% | Everyday cardio, fat burning, base fitness |
| Vigorous | 70–85% | Improving fitness, performance, calorie burn |
| Maximum | 85–100% | Short, hard intervals and peak efforts |
How to measure your resting heart rate
For an accurate target, measure your resting heart rate properly. The best time is first thing in the morning, before you get out of bed. Count your pulse for 60 seconds (or count for 15 seconds and multiply by four), and ideally average it over a few mornings. A fitness tracker or smartwatch that records overnight resting heart rate is even more convenient and reliable.