Target Heart Rate Calculator
Find your maximum heart rate and target training zones for every workout goal — from fat burning to peak performance.
How to use this calculator
Enter your age — your maximum heart rate and all five training zones appear instantly. Optionally enter your resting heart rate (measured first thing in the morning) and enable the Karvonen method for more personalized zones. The Karvonen formula accounts for your fitness level and is more accurate for trained athletes.
Understanding heart rate zones
Training in different heart rate zones produces different fitness adaptations. Zone 2 (fat burn, 60-70%) is the most efficient zone for burning fat and building aerobic base — most of your training should be here. Zone 4-5 intervals improve speed and power but are taxing on the body. A typical training week mixes zones: mostly Zone 2, with some Zone 3-4 work.
Frequently asked questions
Heart rate training zones — full reference
The five-zone model is used by coaches and exercise physiologists to target specific physiological adaptations. Zone boundaries are typically set as percentages of maximum heart rate (MHR). The Karvonen method (which uses heart rate reserve) gives slightly different zone boundaries that account for your fitness level.
| Zone | Name | % of Max HR | Effect | When to use |
|---|---|---|---|---|
| Zone 1 | Active recovery | 50–60% | Recovery, basic aerobic conditioning | Cool-downs, easy days, warm-ups |
| Zone 2 | Aerobic / fat burn | 60–70% | Fat oxidation, aerobic base, mitochondrial density | Long runs, most steady-state cardio |
| Zone 3 | Aerobic endurance | 70–80% | Cardiovascular efficiency, lactate clearance | Tempo runs, moderate-effort sessions |
| Zone 4 | Anaerobic threshold | 80–90% | Lactate threshold improvement, speed endurance | Interval training, race pace work |
| Zone 5 | Maximum effort | 90–100% | VO2 max, peak speed, neuromuscular power | Sprints, short maximal intervals |
Max heart rate formulas compared
The classic 220 minus age formula is widely used but has high individual variability (±10–20 bpm). Several more accurate alternatives have been developed through research.
| Formula | Equation | Notes |
|---|---|---|
| Classic (Fox) | 220 − age | Simple, widely used; ±10–20 bpm individual error |
| Tanaka et al. (2001) | 208 − (0.7 × age) | More accurate for adults >40; validated in large population study |
| Gulati et al. (women) | 206 − (0.88 × age) | Derived from women-only dataset; more accurate for women |
| Measured max HR | Supervised exercise test | Most accurate; requires graded exercise test to exhaustion |
How to use heart rate zones effectively
Research from Scandinavia and elite sports programs consistently shows that the "80/20 rule" produces the best fitness results for recreational and competitive athletes alike.
- ·Spend ~80% of your training time in Zone 1–2 (easy, aerobic pace) — most people train too hard on easy days
- ·Spend ~20% in Zone 4–5 (hard intervals) — this is where VO2 max and speed gains come from
- ·Zone 2 is the "longevity zone" — builds mitochondrial density, metabolic health, and fat-burning capacity over time
- ·Zone 3 ("gray zone") training — moderate intensity — is fatiguing without the adaptation benefits of Zone 4; minimize it
- ·Heart rate drift: on long runs, your HR naturally climbs even at constant pace — this is normal and reflects cardiovascular fatigue
- ·Recovery between hard sessions typically takes 48–72 hours; stick to Zone 1–2 until HR returns to normal for a given pace
How to measure heart rate accurately
The accuracy of your heart rate data determines the quality of zone-based training. Method choice matters significantly.
| Method | Accuracy | Best for |
|---|---|---|
| Chest strap (Polar, Garmin) | High (±1–2 bpm) | Zone training, interval work, cycling |
| Wrist optical (Apple Watch, Garmin) | Medium (±5–15 bpm) | General tracking; less accurate during high-intensity |
| Arm optical band (Whoop, Polar OH1) | Medium-high (±3–8 bpm) | Better than wrist for most activities |
| Manual pulse count | Varies | Emergency use; requires 15-second count × 4 |