Intra-Op Fluid Calculator

Are you an Anesthesia provider? Do you want a quick, reliable way to calculate intraoperative fluid requirements without fumbling through mental math or outdated charts?

This app does just that! Using published references and case studies, we’ve built a tool that calculates weight-based maintenance fluids, preoperative NPO deficits, and allows you to adjust for intraoperative fluid losses by case complexity. Simply enter your patient’s ideal body weight, NPO time, surgery length, and desired mL/kg/hr maintenance rate — the app will generate an hour-by-hour table and chart of recommended fluid administration.

This calculator was created in consultation with practicing Anesthesiologists to reflect recommended best practices and commonly used formulas. The calculations follow well-known guidelines such as the “4-2-1 rule” for maintenance and Furman et al.’s approach for NPO deficit replacement, expanded for adult patients. We continuously review published literature and local practices and will provide updates when changes are made.

The purpose of this app is to serve as a general-use fluid management reference for licensed Anesthesia providers (Anesthesiologists, CRNAs, CAAs, etc.) to support intraoperative planning. It is not intended to replace formal training, institutional policies, or professional judgment. References are provided for transparency and to give users confidence in the underlying formulas.

DISCLAIMER: This app is not a substitute for your clinical judgment, institutional protocols, or published guidelines. Always confirm calculations against your hospital, state, or specialty society recommendations and apply your clinical expertise to each unique patient scenario