This page explains the principles used for DrinkWaterUSA tools and guides. Each tool should state its inputs, units, calculation, intended use, and key limitations near the result.
Water Intake Calculator
The main water calculator applies a rough 30–40 mL per kilogram of body weight range. It converts pounds to kilograms when needed, then presents the arithmetic in liters, US fluid ounces, cups, and glass equivalents. The selected climate and training categories provide context only; they do not change the numeric result.
This weight-based range is a heuristic selected for the tool. It is not a clinically validated personal formula or a recommendation from the National Academies or CDC. The result is not a plain-water quota and does not account for water from food or other beverages.
Other calculators
- Weight and activity tools: the activity fields record context but do not apply an unsupported exercise multiplier.
- Bottle refill calculator: subtracts an amount entered by the user from a user-chosen volume, then expresses the remainder as bottle equivalents.
- Drinking schedule planner: divides a user-entered volume across a selected number of times. It creates a schedule on screen and does not send reminders.
- Daily tracker: totals beverages users enter; it does not estimate water in food.
- Sweat-rate calculator: uses before/after body mass, fluid consumed, urine volume, and session duration to estimate a session rate.
- Printable log: provides a blank record form; it does not calculate a clinical goal.
Reference values and evidence
When we discuss an official population reference, we identify the issuing source and explain what it measures. National Academies Adequate Intake values describe total water from foods and beverages for population groups; they are not outputs of the site’s weight heuristic or exact requirements for every person.
Review and corrections
We review source links and method descriptions when we make material tool changes or receive a credible error report. We record significant updates in the Research and Updates Log. Read the limitations before relying on any estimate.