Target Heart Rate Calculator

What this calculator does

This calculator determines your target heart rate zones for exercise based on your age and resting heart rate. It shows the optimal heart rate ranges for different training goals—fat burning, cardio endurance, and peak performance—so you can train at the right intensity for your fitness objectives.

Heart rate is one of the most accessible and reliable indicators of exercise intensity. Training too easy means slow progress; training too hard means rapid fatigue and increased injury risk. By knowing your target zones, you can structure workouts that are efficient and sustainable, whether you are a beginner building a base, a runner preparing for a race, or someone focused on heart health.

This tool supports both the percentage of max heart rate method and the more accurate Karvonen (heart rate reserve) method, which accounts for your individual resting heart rate.

How to use it

1. Enter your age.
2. Optionally enter your resting heart rate (measured first thing in the morning, in bpm) for the Karvonen method.
3. Review your maximum heart rate, and target zones for light, moderate, vigorous, and peak intensity.

Formulas used

• Estimated max heart rate (HRmax): HRmax = 220 − Age Example: Age 35 → HRmax = 185 bpm. This is an estimate; individual variation can be ±10–15 bpm.

• Percentage of max method: Target HR = HRmax × Intensity % Example: 185 × 0.70 = 130 bpm (70% intensity)

• Karvonen method (heart rate reserve): HRR = HRmax − Resting HR Target HR = (HRR × Intensity %) + Resting HR Example: HRR = 185 − 60 = 125. At 70%: (125 × 0.70) + 60 = 148 bpm.

• Standard zones:

  • Zone 1 (Warm-up / Recovery): 50–60% — light activity, easy conversation
  • Zone 2 (Fat burn / Base): 60–70% — moderate effort, sustainable for long periods
  • Zone 3 (Aerobic / Cardio): 70–80% — challenging but sustainable for 20–60 min
  • Zone 4 (Anaerobic / Threshold): 80–90% — hard effort, 10–20 min sustainable
  • Zone 5 (VO₂ max / Peak): 90–100% — maximum effort, 1–5 min intervals

Examples

Example 1 — Beginner, age 40: HRmax = 180. Zone 2 (fat burn) = 108–126 bpm. Zone 3 (cardio) = 126–144 bpm.

Example 2 — Runner, age 30, resting HR 55 (Karvonen): HRmax = 190. HRR = 135. Zone 3 = (135 × 0.70) + 55 to (135 × 0.80) + 55 = 150–163 bpm.

Example 3 — Older adult, age 65: HRmax = 155. Zone 2 = 93–109 bpm. Zone 3 = 109–124 bpm. Even moderate walking may reach Zone 2, which is excellent for heart health.

Tips and common mistakes

• The 220 − Age formula is an estimate. It works for most people but can be off by 10–15 bpm. If you know your actual max HR from a stress test or field test, use that instead.
• Resting heart rate matters. A trained athlete with a resting HR of 48 has very different target zones than a sedentary person with a resting HR of 78, even at the same age. The Karvonen method accounts for this.
• Measure resting HR correctly. Take it first thing in the morning, before getting out of bed, on 3–5 consecutive days, and average the readings.
• Use a heart rate monitor for accuracy. Wrist-based optical sensors are convenient but can be inaccurate during high-intensity or wrist-moving exercises. Chest straps are more reliable.
• Zone 2 training is underrated. Most endurance coaches recommend spending 80% of training time in Zone 2 to build aerobic base, with only 20% in higher zones. Many recreational athletes train too hard too often.
• Medications affect heart rate. Beta-blockers and some other medications lower max and resting HR. If you take these, consult your doctor for personalized target zones rather than using age-based formulas.