Understanding Heart Rate

Your heart rate refers to the number of times your heart beats in a minute, typically measured in beats per minute (bpm). To use this Target Heart Rate Calculator effectively, it’s important to understand key terms like resting heart rate, maximum heart rate, and heart rate reserve.

What Does the Target Heart Rate Calculator Do?

This calculator estimates your personalized target heart rate zones using one of several methods, including:

1. Haskell & Fox Formula – The classic “220 minus age” rule.

2. Tanaka, Monahan & Seals Formula – A refined method shown to work better across diverse populations.

3. Nes et al. Formula – Another modern, research-backed equation.

4. Karvonen Formula – A personalized method that incorporates your resting heart rate.

5. Rating of Perceived Exertion (RPE) – For those who prefer a non-technical approach based on how hard exercise feels.

Each method has its strengths. The calculator adapts automatically to your input and displays accurate target heart rate zones for various workout intensities (from light warm-ups to maximum-effort sprints).

What Is Maximum Heart Rate?

Maximum heart rate (MHR) is the highest number of heartbeats per minute your body can safely handle during intense activity. The most accurate way to measure it is through a cardiac stress test, where you exercise under medical supervision—usually on a treadmill—while hooked to an ECG. As the workout intensity increases, doctors monitor for signs that indicate you’ve reached your peak heart rate. The theoretical maximum human heart rate is around 300 bpm.

More often, MHR is estimated using age-based formulas. While these provide helpful general estimates, they don’t account for individual differences. For instance, Dr. Fritz Hagerman found that even elite Olympic rowers in their 20s had maximum heart rates ranging from 160 to 220 bpm.

Popular MHR Estimation Formulas:

• Haskell & Fox (1971):
  MHR = 220 - age

• Tanaka, Monahan, & Seals (2001):
  MHR = 208 - 0.7 × age

• Nes et al. (2013):
  MHR = 211 - 0.64 × age

These equations offer useful benchmarks but may vary from person to person.

What Is Resting Heart Rate?

Resting heart rate (RHR) measures how many times your heart beats per minute when you’re at complete rest—awake, calm, and in a comfortable environment. You can check your RHR using a heart monitor or by counting your pulse for 60 seconds.

A healthy adult typically has a resting heart rate between 50 and 90 bpm. While some sources still cite 60–100 bpm as normal, newer research favors the lower range. Athletes often have even lower RHRs due to better cardiovascular efficiency. A rate that’s too high (tachycardia) or too low (bradycardia) could signal a medical concern unless explained by physical fitness.

What Is Heart Rate Reserve?

Heart rate reserve (HRR) is the difference between your maximum heart rate and resting heart rate. It represents the range your heart rate can increase during activity.

Formula:
HRR = MHR - RHR

Example:
If your MHR is 180 bpm and your RHR is 68 bpm:
HRR = 180 - 68 = 112 bpm

Target Heart Rate Zones Explained

Exercise intensity is often measured by how your heart rate increases during physical activity. Your target heart rate zone is a heart rate range that helps you exercise effectively and safely. Working within this zone boosts cardiovascular health and supports fitness goals.

Going too far above this zone can lead to exhaustion or injury, while staying below may not yield enough benefit. The target heart rate is typically divided into five zones:

Heart Rate Zones and Their Benefits:

• Zone 1 (50–60% of MHR):
  Light activity, perfect for warming up, cooling down, or recovery days.

• Zone 2 (60–70% of MHR):
  Ideal for fat burning and building endurance. You can sustain this pace longer.

• Zone 3 (70–80% of MHR):
  Moderate to hard effort; enhances aerobic fitness and speed.

• Zone 4 (80–90% of MHR):
  High-intensity training that builds strength and stamina.

• Zone 5 (90–100% of MHR):
  Maximum effort, suitable for short bursts. It improves peak performance but requires careful recovery.
  

Planning workouts around these zones helps balance progress and recovery.

How to Calculate Target Heart Rate

Method 1: Haskell & Fox Formula

This widely-used method calculates target heart rate zones using only age:

Formula:
MHR = 220 - age

Example:
A 36-year-old has an MHR of:
220 - 36 = 184 bpm

To find their 70–80% zone:
184 × 0.70 = 129 bpm
184 × 0.80 = 147 bpm

So their target heart rate range is 129–147 bpm.

This calculator also supports the Tanaka and Nes formulas mentioned earlier.

Method 2: Karvonen Formula

The Karvonen method considers both your resting heart rate and maximum heart rate for more personalized results.

Formula:
HRR = MHR - RHR
Target HR = RHR + (HRR × intensity%)

Example:
Age: 36, RHR: 70 bpm
MHR = 220 - 36 = 184 bpm
HRR = 184 - 70 = 114 bpm

To find the 70–80% zone:
0.70 × 114 + 70 = 150 bpm
0.80 × 114 + 70 = 161 bpm
Target zone: 150–161 bpm

This is the default method used by our calculator when you enter both age and RHR.

Using RPE (Rating of Perceived Exertion)

The Rating of Perceived Exertion (RPE) helps you judge workout intensity based on how hard you feel you’re working—no equipment needed.

Borg Scale (6–20):

This scale roughly correlates with heart rate. Multiply the RPE number by 10 to estimate bpm.

Formula:
THR = RHR + (MHR - RHR) × (B - 6) / 14
Where B = RPE score

Example:
MHR = 190, RHR = 60, RPE = 13
THR = 60 + (190 - 60) × (13 - 6) / 14 = 125 bpm

Borg CR10 Scale (0–10):

A simpler scale where 0 means no effort and 10 means maximal effort.

Formula:
THR = RHR + (MHR - RHR) × (B / 10)

Example:
MHR = 190, RHR = 60, RPE = 4
THR = 60 + (190 - 60) × 0.4 = 112 bpm

Example Use Case

Example 1:
Maria is 36 years old with a resting heart rate of 70 bpm.
Using the Karvonen method:

• MHR = 220 – 36 = 184 bpm

• HRR = 184 – 70 = 114 bpm

• 70% Zone: 70 + (114 × 0.70) = 150 bpm

• 80% Zone: 70 + (114 × 0.80) = 161 bpm
  ✔ Her target zone: 150–161 bpm

Example 2:
Jason prefers RPE-based workouts. He rates his current jog as an RPE of 4 (moderate).

• MHR: 190 bpm

• RHR: 60 bpm

• Target HR = 60 + (190 – 60) × 0.4 = 112 bpm

This lets Jason self-monitor intensity without a heart rate monitor.

Pro Tip: Pair with a Fitness Tracker

For real-time feedback, use the calculator results alongside a smartwatch or chest strap monitor. Sync your training zones with your wearable to stay in the right range during every workout.

Conclusion

Knowing your target heart rate zones can significantly improve the efficiency and safety of your workouts. Whether you’re looking to burn fat, build endurance, or boost cardiovascular health, this calculator offers multiple methods to personalize your training goals.

Use your age and resting heart rate to explore different estimation techniques like the Haskell & Fox, Karvonen, or RPE-based approaches—and get the most out of every workout session.