Fat Burn & Cardio Heart Rate Calculator
Measure pulse for 60 seconds while sitting calmly. If unknown, leave blank (standard formula will be used).
Estimated Max Heart Rate (MHR)
— BPM
Fat Burning Zone
60% – 70% Intensity
Cardio / Endurance Zone
70% – 80% Intensity
Method used: Standard Formula
Understanding the Fat Burning Zone
When it comes to cardiovascular exercise, not all effort levels yield the same metabolic results. The "Fat Burning Zone" is a specific range of heart rate intensity where your body primarily relies on stored fat as its fuel source, rather than glycogen (carbohydrates).
Typically, this zone is found between 60% and 70% of your maximum heart rate. Exercising in this range is considered moderate intensity—you should be able to carry on a conversation, but your breathing will be heavier than normal.
The Karvonen Formula vs. Standard Formula
This calculator utilizes two different methods depending on the data you provide:
- Standard Formula: If you only input your age, we calculate your Maximum Heart Rate (MHR) using the formula 220 – Age. The zones are then calculated as straight percentages of this max.
- Karvonen Formula: If you input your Resting Heart Rate (RHR), we use the Karvonen method. This is generally more accurate for individuals with varying fitness levels because it accounts for Heart Rate Reserve (HRR). The formula is: Target HR = ((Max HR − Resting HR) × %Intensity) + Resting HR.
Zone Breakdown
Targeting specific heart rate zones can help you achieve different fitness goals:
- Fat Burn Zone (60-70%): Ideal for weight loss and building a base level of fitness. The body oxidizes a higher percentage of fat calories here, though the total calorie burn per minute is lower than high-intensity intervals.
- Cardio Zone (70-80%): Also known as the aerobic zone. This improves cardiovascular endurance, lung capacity, and strengthens the heart. While the percentage of fat burned decreases, the total calories burned increases.
- Peak Zone (80-90%+): This is for high-performance athletic training and intervals (HIIT). It improves speed and power but is difficult to sustain for long periods.
How to Measure Resting Heart Rate
For the most accurate results using this calculator, measure your resting heart rate first thing in the morning before getting out of bed. Find your pulse on your wrist (radial artery) or neck (carotid artery), count the beats for a full 60 seconds, and enter that number into the "Resting Heart Rate" field above.