Health Calculators
Your body is measurable, and these calculators turn measurements into meaning: BMI and waist ratios for screening, BMR and TDEE for energy needs, body fat estimates from a tape measure, heart rate zones for training, and macro targets for nutrition. Every tool here is built on validated equations like Mifflin-St Jeor, and every one is honest about being an estimate from population data, not a diagnosis of you. Use them to track trends, plan sensibly, and ask better questions. They are information, not medical advice: talk to a doctor or registered dietitian before acting on any result that concerns you, starting a diet or exercise program, or managing a health condition. Measured consistently over time, these numbers become one of the most useful health dashboards you can own.
67 free health calculators. Every tool runs instantly in your browser with the formula shown, a worked example, and answers to common questions.
BMR Mifflin estimates a health-related number from standard formulas used in fitness and medicine.
Body Fat estimates a health-related number from standard formulas used in fitness and medicine.
Body Fat Navy estimates a health-related number from standard formulas used in fitness and medicine.
Body Type estimates a health-related number from standard formulas used in fitness and medicine.
Calorie estimates a health-related number from standard formulas used in fitness and medicine.
Calorie Burn estimates a health-related number from standard formulas used in fitness and medicine.
Calorie Deficit estimates a health-related number from standard formulas used in fitness and medicine.
Calorie Goal estimates a health-related number from standard formulas used in fitness and medicine.
Fasting Calculator handles kitchen math: scaling recipes, timing food, and estimating nutrition.
Free Water Deficit estimates a health-related number from standard formulas used in fitness and medicine.
Heart Rate estimates a health-related number from standard formulas used in fitness and medicine.
Heart Rate Zones estimates a health-related number from standard formulas used in fitness and medicine.
Ideal Body Weight estimates a health-related number from standard formulas used in fitness and medicine.
Ideal Weight estimates a health-related number from standard formulas used in fitness and medicine.
Lean Body Mass estimates a health-related number from standard formulas used in fitness and medicine.
Macros estimates a health-related number from standard formulas used in fitness and medicine.
Maffetone HR estimates a health-related number from standard formulas used in fitness and medicine.
Maintenance Fluids estimates a health-related number from standard formulas used in fitness and medicine.
Met Calories estimates a health-related number from standard formulas used in fitness and medicine.
Nap Planner does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Ovulation does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Ovulation Calculator does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Ponderal Index estimates a health-related number from standard formulas used in fitness and medicine.
Pregnancy estimates a health-related number from standard formulas used in fitness and medicine.
Pregnancy Weight estimates a health-related number from standard formulas used in fitness and medicine.
Sleep does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Sleep Debt does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Target Heart Rate estimates a health-related number from standard formulas used in fitness and medicine.
Tdee Macro estimates a health-related number from standard formulas used in fitness and medicine.
Total Body Water estimates a health-related number from standard formulas used in fitness and medicine.
Trimester Date does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Vaccination Schedule does calendar arithmetic: counting days, adding intervals, and finding where dates fall in the week or year.
Vo2 Max estimates a health-related number from standard formulas used in fitness and medicine.
Waist Height Ratio estimates a health-related number from standard formulas used in fitness and medicine.
Waist Hip estimates a health-related number from standard formulas used in fitness and medicine.
Water Intake Health estimates a health-related number from standard formulas used in fitness and medicine.