Heart Rate Zone Calculator

Heart rate training zones divide your effort intensity into five ranges, each producing different physiological adaptations. Training in the right zone for your goal makes your workouts significantly more effective.

This calculator uses two methods. First, the **Tanaka formula** (208 − 0.7 × age) to estimate your maximum heart rate — this is more accurate than the commonly used 220 − age formula, particularly for adults over 40.

Second, the **Karvonen method** (also called Heart Rate Reserve method) to calculate zone boundaries. This accounts for your resting heart rate, which reflects your cardiovascular fitness level. The formula is: Target HR = (Heart Rate Reserve × Intensity%) + Resting HR.

Zone 1 (50–60% HRR) is for active recovery. Zone 2 (60–70%) is the fat-burning aerobic zone — often called the "base" zone. Zone 3 (70–80%) builds aerobic capacity and efficiency. Zone 4 (80–90%) is the threshold zone that increases lactate tolerance and speed. Zone 5 (90–100%) is maximal effort, reserved for intervals and speed work.