How These Zones Are Actually Calculated
The classic "220 minus your age" rule for max heart rate has a real, known error of roughly plus or minus 10 to 12 beats per minute across people of the same age. This calculator uses the Tanaka formula instead, a better-fitting population estimate from a larger dataset. It also uses the Karvonen method rather than a plain percentage of max heart rate, which factors in your resting heart rate, a real, personal fitness marker that plain age-based zones ignore entirely.
MaxHR = 208 - (0.7 × age)
Karvonen (Heart Rate Reserve)
Target HR = ((MaxHR - Resting HR) × %intensity) + Resting HR
No formula here is accurate for a specific individual, only for the population it was built from. Real max heart rate varies meaningfully person to person, even at the identical age.
There is no single fat-burning zone worth chasing. Lower zones burn a higher percentage of calories from fat; higher zones burn more total calories in the same time, fat included. Most of your training time should sit in the lower-to-moderate zones regardless of your goal, with hard efforts used deliberately, not constantly.
Inside SanoobFit's APEX system, real training intensity is tracked as part of the Conditioning standard, part of the Stage 1, Foundation, profile and the backbone of the Endurance program.
Zones Are a Guide. Training in Them Consistently Is the Result
The SanoobFit app builds real, adjusting training around your actual intensity, free to start.
Build My Free PlanFrequently asked questions
Is there a real fat-burning heart rate zone?
Is 220 minus my age an accurate max heart rate?
Should I train near my maximum heart rate often?
This tool gives an estimate to guide your training. It is not medical advice. Check with your doctor before starting high-intensity training, especially if you are new to exercise or have a heart condition.