Heart Rate Zone Calculator (Karvonen Formula)
Calculate precise training zones using your Resting Heart Rate (RHR) for more effective workouts.
Your Personalized Training Zones
Max Heart Rate: BPM
Heart Rate Reserve (HRR): BPM
| Zone | Intensity | Range (BPM) | Benefit |
|---|---|---|---|
| Zone 1 | 50% – 60% | Recovery & Warm-up | |
| Zone 2 | 60% – 70% | Fat Burning & Endurance | |
| Zone 3 | 70% – 80% | Aerobic Fitness | |
| Zone 4 | 80% – 90% | Anaerobic Capacity | |
| Zone 5 | 90% – 100% | Maximum Performance |
Why Calculate Based on Resting Heart Rate?
The standard "220 minus age" formula is a rough estimate. However, the Karvonen Formula, which incorporates your Resting Heart Rate (RHR), is significantly more accurate for athletes. By including your RHR, the calculator determines your Heart Rate Reserve (HRR)—the actual range of beats your heart has available for exertion. This tailors the zones to your specific cardiovascular fitness level.
Understanding Your Training Zones
Zone 1 (Very Light): 50–60% of HRR. Best for warm-ups, cool-downs, and active recovery days. It improves overall health but isn't strenuous.
Zone 2 (Light): 60–70% of HRR. Known as the "Fat Burning Zone." This is the base-building zone where you improve mitochondrial density and fat metabolism. You should be able to hold a conversation.
Zone 3 (Moderate): 70–80% of HRR. This is the aerobic zone. It improves blood circulation and strengthens the heart and skeletal muscles. Breathing becomes deeper.
Zone 4 (Hard): 80–90% of HRR. The anaerobic zone. Here you are training your body to handle lactic acid more efficiently. It is sustainable for shorter bursts, not long durations.
Zone 5 (Maximum): 90–100% of HRR. Sprinting and high-intensity interval training (HIIT). This zone is for peak performance and speed, sustainable only for seconds to a few minutes.
How to Measure Your Resting Heart Rate
For the most accurate results, measure your RHR in the morning immediately after waking up, before getting out of bed. Use a heart rate monitor or count your pulse at your wrist (radial) or neck (carotid) for 60 seconds. Repeat this for three mornings and take the average.
Example Calculation
If you are 40 years old with a resting heart rate of 60 BPM:
- Max HR: 220 – 40 = 180 BPM
- HR Reserve: 180 – 60 = 120 BPM
- Zone 2 Lower Limit (60%): (120 * 0.60) + 60 = 132 BPM