Calculate your 5 heart rate training zones based on age and optional resting heart rate. Know exactly which zone to train in for fat burn, cardio, or peak performance.
Heart rate zones define the intensity of your cardio training. Each zone targets different physiological adaptations — from fat burning and aerobic base building to anaerobic threshold and maximum output. Use the simple method (220 minus age) or the more accurate Karvonen method if you know your resting heart rate.
Formula: Max HR = 220 − age. Karvonen: Target HR = (Max HR − Resting HR) × intensity% + Resting HR
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Download FitFlow FreeCalculate your Body Mass Index (BMI) instantly. Enter your height and weight to determine if you are underweight, normal, overweight, or obese.
NutritionCalculate your Total Daily Energy Expenditure (TDEE). Find out exactly how many calories you burn per day based on activity level, age, weight, and height.
StrengthCalculate your one rep max for any exercise. Enter your weight and reps to estimate your 1RM using the Epley, Brzycki, and Lombardi formulas.
NutritionCalculate your ideal daily macros — protein, carbs, and fat — based on your body stats, activity level, and goal. Whether cutting, bulking, or maintaining.
Body CompositionEstimate your body fat percentage using the U.S. Navy circumference method. Enter your neck, waist, and hip measurements to get an accurate body fat estimate.