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Target Heart Rate Calculator

Calculate your personalized target heart rate training zones using Karvonen and Tanaka formulas. Optimize Zone 2 fat burn and cardio endurance. 100% free.

Cardio Training Zones
years
Enter age to estimate your maximum heart rate
bpm
Your resting pulse upon waking (typically 55–75 bpm)
Karvonen accounts for your resting pulse fitness level
bpm
Override if measured during a clinical treadmill stress test
❤️

Enter your age and resting heart rate above (or click "Try an example") to calculate your personalized 5 cardio training zones and Zone 2 fat burn window.

Zone 2 Target Heart Rate (Aerobic Base & Fat Burn)
136 – 149 bpm
Ideal pace for building mitochondrial density, burning fat, and developing all-day endurance

Cardiovascular Vitals

Estimated Maximum Heart Rate (HRmax)
187 bpm
Heart Rate Reserve (HRR)
127 bpm

The 5 Cardio Training Zones

Zone 1
Active Recovery (50% – 60%)
Very light effort, conversational warm-up & cool-down
124 – 136 bpm
Zone 2
Aerobic Base & Fat Burn (60% – 70%)
Sustainable conversational pace, mitochondrial expansion
136 – 149 bpm
Zone 3
Aerobic Tempo (70% – 80%)
Moderate pace, deeper breathing, cardiovascular capacity
149 – 162 bpm
Zone 4
Lactate Threshold (80% – 90%)
Hard sustainable effort, burns lactic acid, race pace
162 – 174 bpm
Zone 5
VO2 Max / Redline (90% – 100%)
Peak sprint interval, anaerobic power, short bursts
174 – 187 bpm

Custom Target Intensity

%
Custom Target Pulse
155 bpm

How to Use This Calculator

  1. Enter Your Age & Resting Pulse: Input your age and baseline resting heart rate (recorded upon waking before caffeine).
  2. Select Your Calculation Method: The Karvonen Method is recommended because it adjusts for resting fitness levels using Heart Rate Reserve.
  3. Lock in Your Zone 2 Target: Focus 80% of your weekly endurance running, cycling, or rowing training inside Zone 2 for maximum aerobic health.
  4. Calculate Custom Intensities: Use the custom percentage tool below the zones table to find specific heart rates specified in your coach's training plan.

The Formulas

Cardiovascular exercise zones are determined by your Maximum Heart Rate (HRmax) and Heart Rate Reserve (HRR). GrabCalc implements both peer-reviewed age equations and the individualized Karvonen formula:

1. Tanaka Formula (HRmax): 208 - (0.7 × Age) 2. Fox Formula (HRmax): 220 - Age 3. Heart Rate Reserve (HRR): HRmax - HRrest 4. Karvonen Target Heart Rate: HRrest + (HRR × Target Intensity %) 5. Standard Target Heart Rate: HRmax × Target Intensity %

Why Karvonen is Superior: Two individuals of the same age (e.g., 30 years old) have the same age-predicted maximum heart rate (187 bpm). However, an elite marathoner with a resting pulse of 45 bpm has far more usable reserve capacity than an untrained individual with a resting pulse of 75 bpm. Karvonen scales each training zone to individual physiological capacity.

Example: 30-Year-Old with 60 bpm Resting Heart Rate

Athlete Stats: Age 30, Resting Heart Rate = 60 bpm, using the Karvonen + Tanaka model.

1. Maximum Heart Rate (Tanaka):
HRmax = 208 - (0.7 × 30) = 208 - 21 = 187 bpm.

2. Heart Rate Reserve (HRR):
HRR = 187 - 60 = 127 bpm.

3. Zone 2 Range (60% to 70% Intensity):
Lower Limit (60%): 60 + (127 × 0.60) = 60 + 76.2 = 136 bpm.
Upper Limit (70%): 60 + (127 × 0.70) = 60 + 88.9 = 149 bpm.
Zone 2 Target Window: 136 – 149 bpm.

Frequently Asked Questions

Why is the Karvonen formula more accurate than 220 minus age?
The traditional '220 minus age' formula only accounts for chronological age and ignores individual cardiovascular fitness. The Karvonen formula calculates Heart Rate Reserve (Max HR minus Resting HR), which accounts for your baseline resting pulse. A fitter athlete with a lower resting pulse receives personalized, physiological training boundaries rather than a generic guess.
What is the Zone 2 fat burning heart rate and why is it so popular?
Zone 2 (60% to 70% intensity) represents the aerobic base where mitochondrial density increases and your body oxidizes the highest percentage of fat as fuel compared to glycogen. It is popular because it builds tremendous cardiovascular stamina without accumulating excessive muscular fatigue or cortisol.
How do you measure your resting heart rate accurately?
Measure your resting heart rate immediately upon waking up in the morning, before getting out of bed, drinking coffee, or checking your phone. Count your radial pulse at your wrist for 60 seconds, or review your overnight resting heart rate average recorded by a wearable fitness tracker.
What happens if your heart rate goes into Zone 5?
Zone 5 (90% to 100% effort) represents maximal aerobic capacity (VO2 max) and anaerobic glycolytic effort. In this zone, lactic acid accumulates rapidly, speech is impossible, and the effort can only be sustained for 30 seconds to a few minutes. It is used in short high-intensity intervals rather than steady-state cardio.
Can medications or caffeine change your target heart rate zones?
Yes. Medications such as beta-blockers intentionally depress resting and maximum heart rate, while caffeine, decongestants, heat, and dehydration elevate heart rate. If you take cardiovascular medications, use perceived exertion (RPE scale) rather than strict heart rate equations and consult your physician.

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