Health Calculators
19 free health and fitness calculators covering body composition, nutrition, cardio training, pregnancy math, and everyday wellness, built on clinically validated formulas. Not a substitute for medical advice.
Body composition (9)
BMI, body fat, and ideal weight calculations using clinically validated formulas.
- › BMI Calculator
Body Mass Index from height and weight with health category.
- › Reverse BMI Calculator
Find the weight needed to reach any target BMI for your height.
- › Body Fat Calculator
Estimate body fat % via Army tape, Navy, or general formula.
- › Lean Body Mass Calculator
Fat-free mass via the Boer, James, and Hume formulas, plus body-fat mass.
- › Ideal Weight Calculator
Ideal body weight using Devine, Robinson, Miller, and Hamwi formulas.
- › Weight Loss Percentage Calculator
Percentage of body weight lost, with progress toward a goal weight.
- › Waist to Hip Ratio
WHR-based health risk assessment beyond BMI.
- › Body Shape Calculator
Find your body type (hourglass, pear, apple, rectangle, inverted triangle) from bust, waist, and hips.
- › Height Calculator
Convert height between feet/inches and centimeters.
Nutrition & metabolism (2)
Daily energy expenditure, macro splits, and low-carb tracking math.
- › TDEE / Macro Calculator
Daily calorie burn (Mifflin-St Jeor) plus macros for cut, maintain, or bulk.
- › Net Carbs Calculator
Total carbs minus fiber and sugar alcohols for keto and low-carb tracking.
Cardio & training (2)
Heart-rate zones for cardio and one-rep-max estimates for strength training.
- › Target Heart Rate
Max HR and 5 training zones using both 220-age and Karvonen formulas.
- › One Rep Max (1RM)
Estimate your one rep max from any weight and reps, with a training percentage chart.
Medical (1)
Blood sugar tracking and other clinical conversions. Always confirm with your physician.
- › A1C Calculator
Convert between A1C percentage and estimated average glucose (eAG).
Pregnancy & reproductive health (3)
Pregnancy due dates from LMP, conception, ultrasound, or IVF.
- › Pregnancy Due Date
Due date from LMP, conception, ultrasound, or IVF, with week-by-week tracker.
- › IVF Due Date
Due date from embryo transfer date (3-day, 5-day, FET, fresh, or frozen).
- › Menopause Age Calculator
Estimate likely menopause onset from family history and lifestyle factors.
Lifestyle & pets (2)
Popular everyday wellness tools. Educational estimates, not medical, legal, or veterinary advice.
- › Blood Alcohol Calculator (BAC)
Estimate blood alcohol content from drinks, weight, sex, and time (Widmark). Never drive after drinking.
- › Cat Age Calculator
Convert your cat's age into human years on the standard veterinary scale.