Heart Rate Zone Calculator: Fat Burn & Zone 2 Target
Discover your personalised heart rate training zones — from fat-burning Zone 2 to maximum effort Zone 5. Uses the Karvonen formula for precision when resting heart rate is provided. Train smarter, not just harder.
Enter Your Details
Enter your age for basic zones, or add resting heart rate for the more accurate Karvonen method.
Recommended Reading
Learn more about the science behind this calculation, common mistakes, and how to apply it to your fitness goals on the Asterisks Blog.
Related Blog Guides
The 5 Heart Rate Training Zones Explained
Zone 1 — Warm-Up (50–60%)
Very light effort. Used for warm-up, cool-down, and active recovery. Can hold a full conversation easily.
Zone 2 — Fat Burn (60–70%)
The "aerobic base" zone. Burns the highest proportion of fat calories. Key for endurance and sustainable fitness. You can speak in sentences.
Zone 3 — Aerobic (70–80%)
Moderate effort. Improves cardiovascular efficiency. Talking requires some effort. Good for general fitness and tempo runs.
Zone 4 — Anaerobic (80–90%)
Hard effort. Builds speed and raises lactate threshold. Difficult to maintain for more than 10–20 minutes. Breathing is heavy.
Zone 5 — Maximum / VO₂ Max (90–100%)
All-out effort. Only sustainable for short bursts (30 sec–2 min). Used in HIIT and sprint intervals to build peak performance.
Age-Wise Zone 2 (Fat Burn) Heart Rate Reference Chart
Zone 2 training (60–70% of maximum heart rate) is widely regarded by sports scientists as the optimal zone for building aerobic base capacity, improving metabolic flexibility, and maximizing fat oxidation. This table estimates your target Zone 2 heart rate range by age using the standard published Tanaka Max HR formula:
| Age | Estimated Max HR (Tanaka) | Zone 2 (60% - 70% of Max) | Primary Training Benefit |
|---|---|---|---|
| 20 years | 194 bpm | 116 – 136 bpm | Aerobic base building & mitochondrial efficiency |
| 25 years | 191 bpm | 114 – 134 bpm | High proportion of energy derived from fat oxidation |
| 30 years | 187 bpm | 112 – 131 bpm | Active recovery and sustainable endurance foundation |
| 35 years | 184 bpm | 110 – 129 bpm | Improved cardiovascular stroke volume & lower resting HR |
| 40 years | 180 bpm | 108 – 126 bpm | Optimal cellular fitness and metabolic health |
| 45 years | 177 bpm | 106 – 124 bpm | Enhanced lactic acid clearance and fatigue resistance |
| 50 years | 173 bpm | 104 – 121 bpm | Cardiovascular longevity and stamina preservation |
| 55 years | 170 bpm | 102 – 119 bpm | Safe, sustainable cardiovascular conditioning |
| 60 years | 166 bpm | 100 – 116 bpm | Preserves aerobic capacity & supports joint mobility |
| 65 years | 163 bpm | 98 – 114 bpm | Gentle fat-burning stimulus and systemic circulation |
| 70 years | 159 bpm | 95 – 111 bpm | Maintains functional cardiorespiratory health |
Want a Heart Rate-Based Training Plan?
Get a personalised cardio programme using your specific heart rate zones — from a certified fitness trainer.
Start Free Assessment →Related Reading
How the Calculation Works
Asterisks Fit cardiorespiratory training zones are calculated using established clinical exercise physiology models:
- Karvonen Formula (1957): Utilizes the Heart Rate Reserve (HRR) method to establish precise zone boundaries:
HRR = HR_max − HR_rest | Target HR = (HRR × intensity%) + HR_restBy factoring in your resting heart rate, the Karvonen formula accounts for individual cardiovascular fitness and provides a more accurate training stimulus than age-only formulas. - Tanaka Formula (2001) for Max HR: Max Heart Rate is estimated using the Tanaka equation:
HR_max = 208 − (0.7 × Age)This peer-reviewed formula has been shown to have a stronger correlation with laboratory VO₂ Max testing than the traditional Fox & Haskell (220 − Age) equation. - Clinical Application (ACSM Guidelines): Zone classifications align with the American College of Sports Medicine (ACSM) standards for cardiorespiratory fitness, targeting aerobic capacity in Zones 2–3 and anaerobic threshold in Zone 4.
Need Personal Guidance? Talk to a Fitness Trainer.
Get a customised training programme, nutrition plan and ongoing support from a certified personal trainer.
Frequently Asked Questions
Heart rate zones are estimates based on population averages. Individual max HR may vary significantly. Consult a doctor before starting a high-intensity training programme. Read disclaimer.