Fat Burning Zone Calculator

Your details

Your age in whole years. Used to estimate maximum heart rate via 220 minus age.
years
Your resting heart rate in beats per minute (measured first thing in the morning before getting up). Required for the Karvonen method. Typical range is 60-100 bpm; trained athletes often land between 40-60 bpm.
bpm
Karvonen accounts for your resting heart rate, making zones personal. % of MHR is the classic quick method. Zoladz uses fixed adjusters subtracted from your max HR.
Leave at 0 to use the standard estimate (220 minus age). Enter a measured value from a graded exercise test if you have one. Overrides the age-based estimate for all three methods.
bpm
Fat Burn Zone - LowerFat Burn Zone: 137 - 149 bpm
137bpm

Lower bound of the fat-burning target zone

Maximum Heart Rate185bpm
Fat Burn Zone - Upper149bpm
Zone 1 Recovery - Lower125bpm
Zone 1 Recovery - Upper137bpm
Zone 3 Aerobic - Lower149bpm
Zone 3 Aerobic - Upper161bpm
Zone 4 Threshold - Lower161bpm
Zone 4 Threshold - Upper173bpm
Zone 5 Max - Lower173bpm
Zone 5 Max - Upper185bpm
Heart Rate Reserve120bpm
Fat-burn zone summary137 - 149 bpm
137 bpm
Recovery<100Zone 1100-130Fat Burn130-155Aerobic155-175Threshold175-195Max195+

Your fat-burning zone is 137 to 149 bpm.

  • Your fat-burning zone using the Karvonen (heart rate reserve) method is 137 to 149 bpm.
  • At this intensity, your body relies primarily on fat as fuel rather than stored carbohydrates - ideal for steady-state cardio and weight management.
  • Your heart rate reserve is 120 bpm (max 185 bpm minus resting 65 bpm), which personalises the zones compared to a simple percentage method.
  • Aim to spend 2-3 sessions per week in this zone for 30-60 minutes to build aerobic capacity and support fat loss over time.

Next stepTo confirm accuracy, measure your resting heart rate on three consecutive mornings and average the results, then enter it for the Karvonen calculation.

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