Daily Water Intake Calculator

About the Daily Water Intake Calculator

Estimates your daily water needs from body weight, with an extra allowance for exercise. A common guideline is about 33 ml per kg of body weight.

How to use

Enter your body weight and minutes of daily exercise, then click Calculate.

Worked example

70 kg with 30 min exercise → about 2.7 litres per day.

How to use this calculator

1. Enter your body weight in kilograms.
2. Use the calculator to estimate your daily water intake.
3. Review the result and adjust for exercise, heat, or medical advice if needed.

The formula explained

• \(water_daily\) = estimated water to drink per day in milliliters
• \(weight_kg\) = body weight in kilograms
• \(35\) = recommended milliliters of water per kilogram

Step by step method

1. Take your weight in kilograms as the starting value.
2. Multiply that weight by 35 to estimate your daily water need in milliliters.
3. Convert the result if you prefer liters by dividing milliliters by 1000.
4. Use the estimate as a general guide, not a strict medical rule.

Worked example

Here is a simple example for someone who weighs 68 kilograms.

1. Start with \(68\) kilograms.
2. Multiply by \(35\): \(68 \times 35 = 2380\).
3. The estimate is \(2380\) milliliters, which is \(2.38\) liters.

Tips and common mistakes

• This is an estimate, not a diagnosis or a medical prescription.
• Hot weather, exercise, pregnancy, or illness can increase your needs.
• If your doctor has given you a fluid limit, follow that advice instead of the calculator result.
• Remember that water from food and other drinks can also contribute to hydration.

Frequently asked questions