How to Use the Dehydration Fluid Calculator
Select your dehydration level (mild, moderate, or severe) and enter your weight in lbs. The calculator applies evidence-based fluid replacement rates: 15 mL/kg for mild, 30 mL/kg for moderate, and 60 mL/kg for severe dehydration.
Mild dehydration (1–2% body weight loss) presents as thirst and dry mouth and can be resolved with plain water. Moderate dehydration (3–5%) causes headache, dizziness, and reduced urine output — oral rehydration solutions (ORS) or electrolyte drinks are more effective than water alone. Severe dehydration (over 5%) with rapid heartbeat, confusion, or extreme fatigue requires emergency medical treatment.
Drink fluids slowly and consistently rather than all at once. If vomiting or diarrhea is present, electrolyte replenishment is also needed alongside fluid intake.
Frequently Asked Questions
Yes. Pale yellow urine indicates good hydration. Dark yellow signals mild dehydration. Amber or brown-colored urine indicates significant dehydration requiring prompt fluid intake. Colorless urine may indicate over-hydration.
Caffeinated beverages have a mild diuretic effect, making them less effective for rehydration than plain water. When treating dehydration, prioritize water, ORS, or electrolyte drinks over coffee or tea.
The U.S. National Academies recommends about 3.7 L (125 fl oz) per day for men and 2.7 L (91 fl oz) per day for women — from all beverages and food combined. Plain drinking water needs vary by activity level, climate, and individual health.