Water Intake Calculator

Worked example

Example: 70 kg with moderate activity often suggests roughly 2–2.5 L per day before climate adjustments.

How it works

Daily water intake is estimated from body weight using about 33 ml per kilogram, then adjusted for activity level and climate. Results are shown in liters, milliliters, cups, glasses, and fluid ounces. This is a general estimate, not a medical recommendation.

Limitations

This tool provides a general estimate for educational purposes and is not medical advice. Consult a qualified healthcare professional for personal guidance.

Privacy and file handling

Your data stays on your device and is not uploaded.

Accuracy & methodology

This section documents how the calculator works, what it leaves out, and when results were last reviewed. Figures are educational estimates—not professional advice—and are not labeled "current" unless tied to automatically updated reference data.

Formula source or methodology

Daily intake estimate from body weight and activity level using common heuristic formulas (weight-based baseline plus activity adjustment).

Jurisdiction

General wellness estimate

Unit system

Metric or US weight; output in liters or US cups/fl oz per form

Rounding method

Volumes round to practical whole or one-decimal units in the UI

Assumptions

• Healthy adult context
• Activity level adjusts a weight-derived baseline

Known omissions

• Not medical advice. Does not diagnose, treat, or replace clinical assessment.
• Climate, altitude, illness, pregnancy, and breastfeeding needs
• Medical fluid restrictions (heart failure, renal disease)
• Caffeine or alcohol diuretic adjustments

Test cases (automated)

• Valid weight and activity return a positive daily intake
• Zero weight is rejected

Version & last verified

Logic version 1.0. Content and formulas last verified 2026-07-24.