Get your personalised training zones in seconds — choose between the Karvonen (heart rate reserve) method or the classic 220-age formula.
| Zone | % Max HR | Intensity | Benefit |
|---|---|---|---|
| Zone 1 — Recovery | 50–60% | Very light | Recovery, improves blood flow |
| Zone 2 — Fat Burn | 60–70% | Light | Fat metabolism, aerobic base |
| Zone 3 — Aerobic | 70–80% | Moderate | Cardiovascular & endurance fitness |
| Zone 4 — Anaerobic | 80–90% | Hard | Lactate threshold, race pace |
| Zone 5 — Max Effort | 90–100% | Maximum | Peak speed, VO2 max |
Heart rate training zones are percentage ranges of your maximum heart rate (or heart rate reserve) that correspond to different exercise intensities. Each zone produces distinct physiological adaptations: Zone 1 aids recovery, Zone 2 builds aerobic base and fat-burning efficiency, Zone 3 improves aerobic capacity, Zone 4 raises lactate threshold, and Zone 5 develops peak power and speed.
The Karvonen formula (also called the heart rate reserve method) accounts for your resting heart rate when calculating zones. It uses Heart Rate Reserve (HRR = max HR − resting HR) so two people with the same max HR but different fitness levels get appropriately different target zones. It is generally considered more accurate than the simple percentage-of-max-HR method.
The most common estimate is 220 minus your age, which this calculator uses. This is an average — individual max HR can vary by ±10–20 bpm. For a more accurate result you can perform a graded exercise test (usually in a clinical or sports-lab setting) or use a sport-specific field test.
Zone 2 (60–70% of max HR, or the equivalent Karvonen range) is often called the "fat-burning zone" because fat is the primary fuel source at this intensity. However, higher-intensity zones burn more total calories per minute even if a smaller proportion comes from fat. For overall fat loss, a mix of Zone 2 steady-state work and higher-intensity intervals is most effective.
Stream your real-time and resting heart rate data to Home Assistant, n8n, or any webhook endpoint — automatically, in the background.
