How to Calculate Heart Rate to Lose Weight

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Fat Burning Heart Rate Calculator

Optimize your workout for maximum weight loss

Measure while sitting quietly

Your Personal Heart Rate Results

Estimated Maximum Heart Rate: —
Weight Loss Zone (60% – 70%): —
Aerobic/Cardio Zone (70% – 85%): —

*Results calculated using the Karvonen Formula for improved accuracy based on your Heart Rate Reserve.

How to Calculate Heart Rate to Lose Weight

To lose weight effectively, you need to exercise at an intensity that encourages your body to use stored fat as its primary fuel source. This specific intensity level is often called the "Fat Burning Zone." Knowing how to calculate this manually or using a tool ensures you aren't working too hard (which builds endurance but burns fewer fat calories per hour) or too lightly (which doesn't stimulate metabolism).

Understanding the "Fat Burning Zone"

The fat-burning zone typically falls between 60% and 70% of your maximum heart rate. At this intensity, your body burns a higher percentage of calories from fat compared to carbohydrates. While higher intensities (cardio zone) burn more total calories, the 60-70% range is sustainable for longer durations, which is key for consistent weight loss.

The Karvonen Formula: A Better Way to Calculate

While the basic formula is simply "220 minus age," fitness professionals prefer the Karvonen Formula because it accounts for your resting heart rate (RHR). This provides a more personalized target. Here is how it works:

  1. Max Heart Rate (MHR): 220 – Age
  2. Heart Rate Reserve (HRR): MHR – Resting Heart Rate
  3. Target Zone: (HRR × % Intensity) + Resting Heart Rate

Example Calculation

If you are 40 years old with a resting heart rate of 70 BPM, and you want to find the lower end of your weight loss zone (60%):

  • MHR: 220 – 40 = 180 BPM
  • HRR: 180 – 70 = 110
  • Target: (110 × 0.60) + 70 = 136 BPM

Tips for Weight Loss Success

  • Consistency is Key: Aim for 30–60 minutes of activity in your fat-burning zone most days of the week.
  • Monitor Your Pulse: Use a wearable fitness tracker or manually check your pulse at your wrist or neck for 15 seconds and multiply by 4.
  • Mix it Up: Combine steady-state "fat burn" workouts with occasional high-intensity interval training (HIIT) to boost your metabolic rate.
function calculateFatBurnZone() { var age = document.getElementById("age").value; var restingHR = document.getElementById("restingHR").value; var resMaxHR = document.getElementById("resMaxHR"); var resFatBurnZone = document.getElementById("resFatBurnZone"); var resCardioZone = document.getElementById("resCardioZone"); var resultsArea = document.getElementById("resultsArea"); // Validation if (age === "" || age 120) { alert("Please enter a valid age."); return; } if (restingHR === "" || restingHR 120) { alert("Please enter a valid resting heart rate (typically 40-100 BPM)."); return; } // Convert to numbers age = parseFloat(age); restingHR = parseFloat(restingHR); // Calculations var mhr = 220 – age; var hrr = mhr – restingHR; // Fat Burn Zone (60% – 70%) var fatLow = Math.round((hrr * 0.60) + restingHR); var fatHigh = Math.round((hrr * 0.70) + restingHR); // Cardio Zone (70% – 85%) var cardioLow = Math.round((hrr * 0.70) + restingHR); var cardioHigh = Math.round((hrr * 0.85) + restingHR); // Display results resMaxHR.innerHTML = mhr + " BPM"; resFatBurnZone.innerHTML = fatLow + " – " + fatHigh + " BPM"; resCardioZone.innerHTML = cardioLow + " – " + cardioHigh + " BPM"; resultsArea.style.display = "block"; // Smooth scroll to results resultsArea.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); }

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