Water Intake Calculator

The Water Intake Calculator estimates daily fluid intake from body weight, exercise minutes, climate, and pregnancy or breastfeeding status. It reports millilitres, litres, US fluid ounces, cups, 250 ml glasses, and an eight-part hydration schedule.

Calculation method

The model starts with 35 ml per kilogram of body weight. It adds 350 ml for every 30 minutes of activity, then applies the selected climate and condition adjustments. Male input adds a further 300 ml in the current implementation. A 1,500 ml minimum is enforced.

$\text{Base fluid}=\text{Weight in kg}\times35\text{ ml}$ $\text{Daily estimate}=\max(1{,}500,\text{Base fluid}+\text{Activity adjustment}+\text{Climate adjustment}+\text{Condition adjustment})$

Worked example

For 70 kg, 30 minutes of activity, normal climate, and no condition:

1. Base: 70 x 35 = 2,450 ml.
2. Activity: 30 / 30 x 350 = 350 ml.
3. Daily estimate: 2,800 ml, or 2.8 litres before display rounding.

Questions

Is this the same as total water from food and drinks?

No. It is a drink-intake planning estimate. Food moisture, medications, illness, heat exposure, and clinician instructions are not individually modeled.

Should I drink exactly the displayed amount?

No. Hydration needs vary. Use thirst, urine colour, activity conditions, and medical guidance rather than treating the estimate as a prescription.

Does pregnancy or breastfeeding change the estimate?

Yes. The module adds 300 ml for pregnancy and 700 ml for breastfeeding when selected.

Health notice and limitations

This calculator is educational and does not replace medical advice. People with kidney, heart, liver, endocrine, or fluid-balance conditions should follow their clinician's guidance. The model does not account for all sources of fluid or individual health factors.