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Both calculators run independently — change the inputs on either side to compare results.

Fitness

BMI Calculator

Calculate Body Mass Index (BMI) — body weight in kg divided by height in metres squared — to screen for under/overweight categories. The most widely used population-level fitness and health risk metric, with known limitations for athletes and unusual body compositions.

Underweight<18.5Normal18.5–25Overweight25–30Obese I30–35Obese II+35+
Fitness

Body Water Percentage Calculator

Estimate body water percentage using a simple age-, gender-, and weight-adjusted formula. Use it as a rough wellness indicator alongside BMI and body fat percentage — accurate measurement requires bioelectrical impedance analysis (BIA) or DEXA scans.

Key differences

BMI CalculatorBody Water Percentage Calculator
CategoryFitnessFitness
Inputs required23
ResultYour BMIBody Water (kg)
What it doesCalculate Body Mass Index (BMI) — body weight in kg divided by height in metres squared — to screen for under/overweight categories. The most widely used population-level fitness and health risk metric, with known limitations for athletes and unusual body compositions.Estimate body water percentage using a simple age-, gender-, and weight-adjusted formula. Use it as a rough wellness indicator alongside BMI and body fat percentage — accurate measurement requires bioelectrical impedance analysis (BIA) or DEXA scans.