A common rule of thumb sets daily water intake from body weight. This formula gives a baseline you can adjust for activity and climate.
Water (oz) = Weight (lb) × 0.5
What the terms mean
| Symbol | Meaning |
|---|---|
| Water | Daily water, in fluid ounces |
| Weight | Body weight, in pounds |
| 0.5 | Ounces per pound (use up to 0.67) |
Worked example
A 160 lb person needs about 160 × 0.5 = 80 oz, roughly ten 8 oz glasses a day.
Add for sweat and heat. Exercise, heat, and altitude all raise the requirement. Use the higher 0.67 factor on active or hot days, and let thirst guide the rest.
FAQ
Does this formula apply to any brewing method? The underlying hydration ratio applies broadly, but ideal ratios differ by method. Espresso, pour-over, French press, and cold brew each have their own typical range, so use the ratio appropriate to your specific brewing method.
See the Hydration Calculator and the Water Intake Calculator.