Health & Fitness Calculators

Health goals are easier to reach when you can measure where you are starting from. This collection of 33 free health and fitness calculators helps you understand your body, plan your nutrition, train smarter, and keep track of important dates and milestones. Everything runs locally in your browser — private, instant, and free, with no accounts and nothing stored.

Start with the basics. The BMI Calculator checks your Body Mass Index against healthy ranges, and the Body Fat Calculator goes deeper with Navy-method circumference measurements and BMI-based formulas. If you are managing your weight, the Calorie Calculator estimates how much to eat for loss, maintenance, or muscle gain, while the TDEE Calculator adjusts that target for your real activity level. Lifters can estimate a one-rep max from any set using four proven formulas, and runners can turn workouts into splits and race predictions with the Pace Calculator.

This category also covers pregnancy and everyday wellness. Expecting parents can follow trimesters and milestones, estimate a due date from the last menstrual period or conception date, predict ovulation and fertile windows, and check recommended pregnancy weight gain. There are tools for sleep cycles, daily protein, carbohydrate, fat and water intake, target heart rate zones, calories burned during exercise, and clinical-style estimates such as GFR, body surface area, and lean body mass.

Every result comes with a plain-English explanation of what the number means and how it was calculated. These tools are for information and education only — they are not medical advice, and a qualified healthcare professional should always guide health decisions.