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Target Heart Rate Calculator

Calculate your target heart rate zones for fat burning, cardio, and peak performance. Based on Karvonen formula and max heart rate.

What is Target Heart Rate Calculator?

A target heart rate calculator determines the heart rate zones you should aim for during exercise to achieve specific fitness goals. Zone 1 supports recovery, Zone 2 burns fat, Zone 3 builds aerobic capacity, Zone 4 increases speed, and Zone 5 is maximum effort. Adding your resting heart rate enables the Karvonen formula, which produces more personalised zones.

How to use

  1. 1 Enter your age — the calculator uses the 220 minus age formula to estimate your maximum heart rate.
  2. 2 Optionally enter your resting heart rate (measured first thing in the morning) to enable the Karvonen method.
  3. 3 Review the five heart rate zones with their beats-per-minute ranges.
  4. 4 Match your exercise intensity to the zone that fits your training goal for the day.
  5. 5 Use a heart rate monitor during workouts to stay within your target zone.

Formula

Max HR = 220 - Age | Karvonen zone: Target HR = Resting HR + (Max HR - Resting HR) x Zone %

Example calculation

A 35-year-old with a resting heart rate of 60 bpm has an estimated max HR of 185 bpm and a heart rate reserve of 125 bpm. Their Zone 2 fat-burning range using the Karvonen formula is 60 + (125 x 0.60) to 60 + (125 x 0.70) = 135 to 148 bpm.

Frequently asked questions

Is the 220 minus age formula accurate?

It is a reasonable population average but can be off by 10 to 20 bpm for individuals. Factors like genetics, fitness level, and medications all affect true maximum heart rate. A supervised stress test gives a more precise max HR.

What is the Karvonen formula?

The Karvonen formula uses your heart rate reserve — the difference between max HR and resting HR — to calculate training zones. It accounts for individual fitness level and tends to produce more accurate zones than using max HR alone.

What zone should I train in for weight loss?

Zone 2 (60-70% of max HR) is often called the fat-burning zone because a higher proportion of fuel comes from fat at this intensity. However, higher-intensity training burns more total calories, which also contributes to fat loss.

How do I measure my resting heart rate?

Measure it first thing in the morning before getting out of bed. Place two fingers on your wrist or neck, count beats for 60 seconds. A typical resting HR for adults is 60 to 100 bpm; trained athletes often measure 40 to 60 bpm.

Can I exercise in Zone 5 regularly?

Zone 5 (90-100% max HR) should only be sustained for very short bursts and requires significant recovery time. Training in Zone 5 too frequently without adequate recovery leads to overtraining and increased injury risk.