Heart Rate Zone Calculator: Train at the Right Intensity for Your Goal
Every heart rate zone produces a different training adaptation. Zone 2 burns fat and builds aerobic base. Zone 4 pushes your lactate threshold. Zone 5 raises VO2 Max. Train in the wrong zone and you are leaving results on the table. This calculator gives you all five zones personalised to your age and resting heart rate.
The Formula — Karvonen Method
This calculator uses the Karvonen (Heart Rate Reserve) method, which gives more personalised zones than simple percentage-of-max formulas by accounting for your individual resting heart rate.
Max HR = 220 − Age
HRR = Max HR − Resting HR
Zone Target = (HRR × Zone%) + Resting HR
Worked Example
Age 34, Resting HR 58 bpm.
Max HR = 186 | HRR = 186 − 58 = 128
Zone 2 (60–70%): (128 × 0.60) + 58 to (128 × 0.70) + 58 = 135–148 bpm
Get all five zones instantly with our Heart Rate Zone Calculator.
Your Five Training Zones
| Zone | Intensity | Feel | Primary Benefit |
|---|
| Zone 1 | 50–60% | Very easy, full conversations | Active recovery, warm-up |
| Zone 2 | 60–70% | Comfortable, can speak in sentences | Fat burning, aerobic base |
| Zone 3 | 70–80% | Moderate, broken sentences | Aerobic conditioning |
| Zone 4 | 80–90% | Hard, short phrases only | Lactate threshold, speed |
| Zone 5 | 90–100% | Maximum, cannot speak | VO2 Max, peak power |
Why Zone Training Works
- Maximise each session's purpose. Zone 2 work at Zone 3 intensity fails to produce the fat adaptation benefits you are targeting.
- Prevent overtraining. Most recreational athletes train everything at a moderate-hard intensity — not hard enough to drive adaptation, but too hard to recover properly.
- Structured progression. Building Zone 2 capacity first makes high-intensity Zone 4/5 work more effective later.
- Track fitness improvement. As you get fitter, your HR at the same pace or power output drops — measurable evidence of aerobic development.
Practical Tips
Measure resting HR correctly. Lie still for 5 minutes upon waking, before caffeine. Average 3 consecutive mornings for accuracy.
Apply the 80/20 rule. The polarised training model — 80% easy (Zone 1–2), 20% hard (Zone 4–5) — is well-supported by endurance research for most athletes.
Use a chest strap monitor. Wrist-based optical sensors are convenient but can lag 10–15 seconds and miss HR peaks during high-intensity intervals. A chest strap is more accurate for zone-specific training.
Recalculate when fitness changes. As resting HR improves, your zones shift — update every 3–6 months.
Final Thoughts
Training zones transform exercise from general movement into precision work. With your personal zones, every session has a clear purpose and a measurable physiological target.
Calculate your personalised zones with our free Heart Rate Zone Calculator.
Consult your doctor before starting any vigorous new exercise program, especially if you have a cardiovascular condition.