Maintenance fluids are essential for sustaining hydration, electrolyte balance, and metabolic function in patients who cannot maintain adequate oral intake. The Maintenance Fluids Calculator helps clinicians quickly determine the baseline daily fluid needs, most commonly using the Holliday–Segar method. This formula calculates requirements by assigning 100 mL/kg for the first 10 kg of body weight, 50 mL/kg for the next 10 kg, and 20 mL/kg for each additional kilogram. This structured approach simplifies estimation and ensures that patients receive fluids appropriate for their size.

Accurate fluid management is especially important in pediatrics, where fluid needs vary significantly with body weight, and both dehydration and fluid overload carry serious risks. In adults, the calculator provides a reference for standard maintenance needs but must be adapted to clinical context, such as comorbidities, renal function, or ongoing losses from fever, diarrhea, or drains. Overestimating fluids can lead to complications such as pulmonary edema or electrolyte imbalance, while underestimating may worsen dehydration and organ dysfunction.

By providing a quick, evidence-based calculation, the Maintenance Fluids Calculator serves as a valuable decision support tool. It simplifies routine care, reduces calculation errors, and enhances patient safety, particularly in children and critically ill patients where precision is vital.