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

Water Usage

Daily Water Intake Calculator

Estimate the daily water intake (in liters) a person should target based on body weight and physical activity level. Use this as a starting point for hydration planning, not a medical prescription.

Fill in the required fields to see your result.
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+
Fill in the required fields to see your result.

Key differences

Daily Water Intake CalculatorBMI Calculator
CategoryWater UsageFitness
Inputs required22
ResultDaily Water Intake (liters)Your BMI
What it doesEstimate the daily water intake (in liters) a person should target based on body weight and physical activity level. Use this as a starting point for hydration planning, not a medical prescription.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.