Water Intake Calculator Formula

Understand the math behind the water intake calculator. Each variable explained with a worked example.

Use the Water Intake Calculator

Formulas Used

Water (ounces/day)

water_oz = ounces

Water (cups/day)

water_cups = ounces / 8

Water (liters/day)

water_liters = ounces * 0.0295735

Variables

VariableDescriptionDefault
weight_lbsBody Weight(lbs)170
ouncesDerived value= weight_lbs / 2calculated

How It Works

Water Intake Rule of Thumb

Ounces per day = Body Weight (lbs) / 2

This is a general guideline. Actual needs vary based on activity, climate, and health conditions.

Conversions

  • 8 oz = 1 cup
  • 33.814 oz = 1 liter

    • Worked Example

    A person weighing 170 lbs.

    weight_lbs = 170
    1. 01Water = 170 / 2 = 85 oz per day
    2. 02In cups = 85 / 8 = 10.6 cups
    3. 03In liters = 85 x 0.0296 = 2.51 liters

    Ready to run the numbers?

    Open Water Intake Calculator