Why Fat Burning Zone and Zone 2 Are the Same Thing
Both terms describe the same 60–70% heart rate reserve range. "Fat burning zone" is the framing you'll see in general fitness and weight-loss content, while "Zone 2" is the term endurance coaches and athletes use for the same range in the context of aerobic base training. The bpm numbers don't change, only the reason you might be training there does.
For the full explanation of why this zone burns a higher percentage of fat, and how it compares to higher-intensity training, see our guides on the fat burning heart rate zone and Zone 2 training.
How This Calculator Works
Heart Rate Reserve (HRR) = Max HR − Resting HR
Zone 2 / Fat Burning Range = Resting HR + (60% to 70% × HRR)
This is the same heart rate reserve method used by the full Karvonen calculator, which is why it accounts for your resting heart rate rather than just a flat percentage of max HR. Max heart rate is estimated using the standard 220-minus-age formula. If you have a tested max heart rate that differs from the age-based estimate, or want a more refined estimate from the Tanaka formula, use the full Karvonen calculator, where you can enter it directly.
Frequently Asked Questions
Common questions about the fat burning heart rate zone and Zone 2 training.
Your fat burning heart rate is the range where your body draws a higher proportion of its energy from fat rather than carbohydrates, typically 60 to 70% of your heart rate reserve. Enter your age and resting heart rate above to calculate your exact range.
Zone 2 is the same range as the fat burning zone, roughly 60 to 70% of your heart rate reserve. It's the pace most endurance athletes use for the bulk of their aerobic base training, conversational effort that's sustainable for long periods. See our full Zone 2 training guide for how to structure sessions around it.
It burns a higher percentage of fat per minute, but higher-intensity exercise often burns more total calories in the same time. For weight loss specifically, total calories burned across a week tends to matter more than which fuel source is used in any single session. See our guide on heart rate zones for weight loss for the full comparison.
It uses the Karvonen formula: subtract your resting heart rate from your estimated max heart rate (220 minus your age) to get your heart rate reserve, then take 60 to 70% of that reserve and add it back to your resting heart rate.
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Want Your Full Breakdown?
Your fat burning / Zone 2 range is just one of 5 personalized training zones. Pair your resting heart rate with your max heart rate using the Karvonen method to see all of them.
