Heart Rate Zone Calculator
Use the Karvonen formula to find your 5 training heart rate zones. Enter your age, resting heart rate, and max heart rate (or let us estimate it).
Your 5 Training Zones
| Zone | % of HRR | BPM Range | Perceived Exertion | Benefit |
|---|
Max HR: bpm | Resting HR: bpm | HR Reserve: bpm
Understanding the 5 Heart Rate Zones
Heart rate training zones help you exercise at the right intensity for your goals. The Karvonen formula (also called the heart rate reserve method) is more accurate than the simple percentage-of-max method because it accounts for your resting heart rate.
Zone 1 — Very Light (50–60%): Recovery and warm-up. You can hold a full conversation. Benefits: improves blood flow, promotes recovery, builds aerobic base.
Zone 2 — Light (60–70%): The fat-burning zone. Conversational pace. Benefits: increases mitochondrial density, improves fat oxidation, builds endurance. This is where most of your training should be.
Zone 3 — Moderate (70–80%): Tempo pace. Short sentences possible. Benefits: improves lactate threshold, increases cardiovascular efficiency, builds aerobic power.
Zone 4 — Hard (80–90%): Threshold pace. One or two words at a time. Benefits: raises lactate threshold, improves VO2 max, increases speed.
Zone 5 — Maximum (90–100%): Sprint pace. Can't speak. Benefits: develops top-end speed, increases power output, improves neuromuscular coordination.
Method
HR Reserve (Karvonen) = MHR - RHR
Target HR = (HR Reserve × %Intensity) + RHR
For example, a 30-year-old with RHR 65 and estimated MHR 190: Zone 2 target = ((190-65) × 0.65) + 65 = 146 bpm.
Max HR Formulas
If you didn't enter a max HR, we estimate it using the Tanaka formula: 208 − (0.7 × age). This is more accurate than the old 220 - age formula, especially for adults over 40.
For the most accurate results, measure your actual max HR through a field test (e.g., 5-minute hard run, 2-minute max effort) or a lab test.