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Heart Rate Training Zones Calculator

Find your personalized cardio training zones using the Karvonen formula.

Tip: measure resting heart rate first thing in the morning, before getting out of bed.

What is it?

This calculator finds your personalized heart rate training zones using the Karvonen formula, which factors in your resting heart rate for a more accurate result than simple max-heart-rate-only methods.

Formula

Max HR = 220 − Age
Target HR = Resting HR + Intensity% × (Max HR − Resting HR)

Formula Explanation

The Karvonen formula uses your Heart Rate Reserve (HRR) — the gap between your max heart rate and resting heart rate — instead of just a percentage of max heart rate. Because it accounts for your resting heart rate, it adjusts to your actual fitness level rather than treating everyone the same age as identical.

Example Calculation

A 30-year-old with a resting heart rate of 65 bpm has a Max HR of 190 bpm and an HRR of 125 bpm. Their Zone 3 (Moderate, 70-80%) range is 153–165 bpm.

How to Use

  1. Enter your age.
  2. Enter your resting heart rate, ideally measured first thing in the morning.
  3. Review your five training zones, each with a target bpm range.

Benefits

  • More personalized than flat percentage-of-max-HR charts, since it accounts for your resting heart rate.
  • Breaks training into five clear zones so you can match effort to your workout goal.
  • Useful for any cardio activity — running, cycling, swimming, or general fitness training.

Use Cases

  • Structuring interval training around specific heart rate zones.
  • Making sure recovery or warm-up sessions stay in Zone 1-2 instead of overtraining.
  • Pairing with a heart rate monitor or fitness tracker during workouts.

What Your Result Means

Each zone represents a different training intensity. Lower zones (1-2) build aerobic endurance and burn a higher percentage of fat, while higher zones (4-5) build anaerobic capacity and speed but can only be sustained briefly.

Tips

  • Most endurance training should happen in Zone 2, with only a small portion of weekly training in Zone 4-5.
  • Re-check your resting heart rate every few weeks — it tends to drop as cardiovascular fitness improves.
  • Use a chest-strap or wrist heart rate monitor for the most accurate real-time zone tracking.

Common Mistakes

  • Using age-predicted max HR (220 − age) as an exact number — it's a population average and can be off by 10-15 bpm for any individual.
  • Training mostly in Zone 4-5, which builds fatigue faster than fitness for most endurance goals.
  • Measuring resting heart rate after caffeine, stress, or activity instead of at rest.

FAQs

What is the Karvonen formula?

It's a method for calculating target heart rate training zones that uses heart rate reserve (max HR minus resting HR) rather than just a percentage of max heart rate.

Which zone should I train in to lose fat?

Zone 2 (60-70% of heart rate reserve) is typically the most efficient for sustained fat burning and aerobic base building.

Is the 220 minus age formula accurate?

It's a widely used estimate, but individual max heart rate can vary by 10-15 bpm from this formula — a lab or field fitness test gives a more precise number.

How do I measure my resting heart rate?

Check your pulse for 60 seconds immediately after waking up, before getting out of bed, for the most accurate resting reading.

This tool provides general fitness estimates and is not a substitute for guidance from a doctor or certified trainer, especially if you have a heart condition.

Last updated: July 26, 2026