About TheFitnessCalculator.com

TheFitnessCalculator.com is a free collection of health and fitness calculators. Every tool runs in your browser, needs no sign-up, and stores none of your numbers. The goal is simple: give you fast, accurate answers to the everyday questions people ask about weight, calories and body composition.

What you can work out here

• BMI — whether your weight sits in a healthy range for your height.
• Calories / TDEE — how much energy you burn a day and targets for losing, maintaining or gaining weight.
• Body fat — an estimate from the U.S. Navy tape method.
• Ideal weight — a healthy target range using the Devine and Robinson formulas.
• Water intake — a daily hydration estimate based on your weight and activity.

How the numbers are calculated

The tools use established equations — Mifflin–St Jeor for metabolism, the U.S. Navy circumference method for body fat, and standard BMI and ideal-weight formulas. Both metric and imperial units are supported, and you can switch units on any single tool.

A note on accuracy

These calculators give general estimates for healthy adults. They are educational tools, not medical advice, and they do not replace guidance from a doctor or dietitian. If you have a medical condition, are pregnant, or are an athlete with unusual body composition, treat the results as a rough guide only.

Questions or feedback? Visit our contact page.