FitCalc

Fat Burning Heart Rate Calculator

The heart-rate range where fat contributes the most to your energy use.

Quick answer: The fat-burning zone is roughly 60–70% of maximum heart rate. At a max HR of 185 that is about 111–130 bpm. It burns a higher proportion of fat, but higher intensities burn more total calories.

years
bpm

Optional — used for the Karvonen zone ranges.

Estimated max HR
183.5 bpm
Fat-burning zone (60–70%)
110.1–128.5 bpm
Max HR183.5 bpm
Fat-burning (60–70% of max)110.1–128.5 bpm
Zone 3 start (70%)146.0 bpm
Zone 4 start (80%)159.0 bpm
Zone 5 start (90%)171.0 bpm

Training zones (Karvonen method)

ZoneHeart rateWhat it trains
Zone 1 — Very light (50–60%)122134 bpmWarm-up, recovery, active daily movement
Zone 2 — Light (60–70%)134146 bpmBase endurance, fat oxidation, long easy sessions
Zone 3 — Moderate (70–80%)146159 bpmAerobic conditioning, tempo work
Zone 4 — Hard (80–90%)159171 bpmThreshold intervals, speed endurance
Zone 5 — Maximum (90–100%)171184 bpmVO2 max intervals, short maximal efforts

Max heart rate is estimated from age; individual values vary by 10–15 bpm. Zones use the Karvonen method, which folds in resting heart rate for a more personal range. If you have a heart condition or take medication that affects heart rate, follow medical advice rather than these estimates.

Core facts
Zone60 – 70% of max HR
At max 185About 111 – 130 bpm
Trade-offHigher fat % vs lower total
InputsAge, resting HR

What is Fat Burning Heart Rate Calculator?

At low-to-moderate intensity your body draws a higher proportion of its energy from fat; as intensity rises, carbohydrate takes over. The 'fat-burning zone' describes the lower-intensity range where that fat proportion peaks, generally around 60–70% of maximum heart rate. The catch is that proportion and total are different things: at easy pace you might burn 60% of your energy from fat, but at a much lower total, while a hard session burns a smaller percentage of a far larger number. For weight loss, what matters is the total calorie deficit across the day, not the fuel mix of any one session. The zone is still useful for building aerobic base and for training that you can sustain for a long time.

Common Uses for Fat Burning Heart Rate Calculator

  • Find the heart-rate range for steady fat-burning exercise
  • Understand the fat-proportion versus total-calories trade-off
  • Guide long, low-intensity cardio sessions
  • Set a target for active recovery work

Frequently Asked Questions

Does the fat-burning zone burn more fat?
It burns a higher proportion of calories from fat, but fewer total calories. For fat loss over a day, total energy balance matters more than the proportion in one session.
Should I only train in the fat-burning zone?
No. A mix of easy and hard sessions is best for fitness and for total calories burned. Easy work builds base and is sustainable; hard work improves capacity.
Why is my fat-burning zone so low?
Because it is a percentage of your maximum heart rate, so it sits below your comfortable running pace for many people. That is expected — it is meant to feel easy.

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