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Target Heart-Rate(THR) Calculator

Determine your ideal cardio training range with this effective tool

A super-simple tool to determine your ‘THR’ for fat-burning and cardio-conditioning

To get the best results from your aerobic exercise, it’s wise to keep your heart-rate in the range which will give you (1) The best fat-burning potential, and (2) Enable your heart and lungs to get the maximum health benefits.

In simple terms, we’re talking about how fast your heart should beat while doing sustained physical activity using oxygen (aerobic).

Why? Because different cardiovascular intensity-levels cause different physiological effects and provide different outcomes.

Useful to note:

  • If your heart-rate is below THR, there’s pretty much no cardio-conditioning or fat-burning going on.

  • If your heart-rate is above THR, then you’re in ‘anaerobic‘ territory, where a different physiological mechanism engages. Think of activities like weight-training or sprinting (HIIT). These activities use your non-oxygen energy system and, unlike jogging, can only be sustained for very short periods. Although great for explosive speed and muscle-development, it’s not topical here.

  • What determines ‘target’ heart-rate?

    Knowing what cardio intensity to aim for – is a big part of successfully realizing any fitness goal (including the Sensible Fitness Program).

    To be clear, Target (or Training) Heart-Rate is a desired range to reach and maintain during aerobic exercise to burn as many calories as possible while your heart and lungs receive optimal conditioning from the exertion. THR is a theoretical and individual range based on age. However, your physical condition, gender and past training also influence calculations.

    We’ll look at two ways of calculating THR – both of which use maximum heart-rate (HRmax) as a basis – and I’ll explain why I prefer the second one.

    1. An example using the most basic method

    A widely-accepted formula for maximum heart-rate is:

    THR = 220 - age × % intensity


    A 40-year old person would therefore have a HRmax of 180 (HRmax of 220 minus age).

  • 50% Intensity: (220 − (age = 40)) × 0.50 → 90 bpm

  • 85% Intensity: (220 − (age = 40)) × 0.85 → 154bpm

  • This is a relatively simple way to determine the lower and upper numbers for THR. Although quick and easy, I personally prefer using the Karvonen method instead.

    2. A more accurate method using a simple formula

    I consider the Karvonen method a better option for its accuracy, since it factors in resting heart-rate (RHR). It is also the basis for the calculator below.

    Before touching on the formula, keep in mind: the aim is to obtain THR for an intensity range of 50–85% – so the calculator as set up as such.

    Why 50 to 85? 

    These numbers represent the most commonly recommended average lower end of ‘moderate’ and the higher end of ‘vigorous’ training intensities by most health and wellness institutes like the American Heart Association.

    They recommend exercising within 50 to 85 percent of your MHR for at least 20-30 minutes per session, to get the best results from aerobic exercise. Here, we're talking low and moderate-intensity steady state (LISS/MISS) cardio.

    MHR is the upper limit of what your cardiovascular system is estimated to be able to cope with during physical activity. (There's more detail about this on the cardio training page.)

    On the other hand, your anaerobic zone commences at the upper threshold of your Training Heart-Rate (THR), and where you'd want to focus when doing high-intensity interval training (HIIT) cardio. (The Borg RPE scales are handy in helping you to gauge your limits.)

    The Karvonen formula

    As mentioned, the formula factors in resting heart-rate (HRrest) to calculate target heart-rate:

    THR = ((HRmax − HRrest) × % intensity) + HR

    Again using the universal HRmax of 220, a 40-year old person with a resting heart-rate of 60 beats per minute, has the following THR:

  • 50% Intensity: ((180 − 60) × 0.50) + 60 → 120 bpm

  • 85% Intensity: ((180 − 60) × 0.85) + 60 → 162 bpm

  • Based on this formula, use the calculator below to get your 'range' or 'zone' (50-85% of Maximal Heart-Rate (MHR), based on your age and condition.

    Simply click the blue button:

    NOTE: Since the Karvonen method takes resting heart-rate (RHR) and MHR into account to establish heart-rate reserve (HRR), it is a relatively accurate method for estimating THR. Because a low RHR is a reliable indicator of fitness, the Karvonen formula is more successful at predicting THR zones for both 'fit' and 'unfit' individuals.

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