# Intra-Op Fluid Calculator — Maintenance crystalloid calc > Anesthesia fluid calculator for intraoperative fluid management. (iPhone/iPad app by Tyler Interrante.) - Source: https://appshunter.io/ios/app/intra-op-fluid-calculator/id6748544694 (this page in markdown: same URL + `.md`) - Developer: [Tyler Interrante](https://appshunter.io/developer/1821552598) - Category: Medical, Education - Price: $3.99 - Rating: 5.00/5 from 3 App Store ratings · 3 written reviews indexed - Age rating: 17+ - Requires: iOS 18.4 · 2 MB - Languages: American English - Released: 2025-09-16 - Data updated: 2026-07-18 - Monetization: paid - User reviews in markdown: https://appshunter.io/ios/app/intra-op-fluid-calculator/id6748544694/reviews.md ## What is Intra? 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you want a quick, reliable way to calculate intraoperative fluid requirements without fumbling through mental math or outdated charts?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 ## Key features - Weight-based maintenance fluid calculation - Preoperative NPO deficit calculation - Intraoperative fluid loss adjustment - Hour-by-hour fluid administration table and chart - Consultation with practicing Anesthesiologists - References to medical guidelines ## Chart rankings - #199 in Top Paid · Medical (US App Store) ## Recent user reviews (3 of 3) All indexed reviews: https://appshunter.io/ios/app/intra-op-fluid-calculator/id6748544694/reviews.md ### 5/5 — Easy to use :) *2025-09-19* The intra-op fluid calculator app is incredibly straightforward and user-friendly. The interface is clean which makes calculations quick before or during a case. Perfect for anesthesia providers looking for a simple, reliable tool in the OR. **Developer response:** Thanks for your review! We hope provide new tools with just as a simplistic view soon! ### 5/5 — Amazing app! *2025-09-19* Excellent app and very simple to use. I use it every time I work a long surgical case and found it does a great job keeping a patient euvolemic. **Developer response:** Thanks for your review! We hope provide new tools with just as a simplistic view soon! ### 5/5 — Awesome *2025-09-18* I found it easy to use and aesthetically pleasing! Would recommend to my colleagues. **Developer response:** Thanks for your review! We hope provide new tools with just as a simplistic view soon! ## Frequently asked questions about Intra ### How does Intra-Op Fluid Calculator help anesthesia providers? Intra-Op Fluid Calculator provides a quick and reliable method for calculating intraoperative fluid requirements. It helps avoid manual calculations or outdated charts by generating hour-by-hour recommendations for fluid administration based on patient data and surgery specifics. ### What medical guidelines does Intra-Op Fluid Calculator follow? The app's calculations are based on well-known guidelines such as the '4-2-1 rule' for maintenance fluids and Furman et al.'s approach for NPO deficit replacement, expanded for adult patients. References are provided for transparency and user confidence. ### What information do I need to input into Intra-Op Fluid Calculator? To use the calculator, you need to enter the patient's ideal body weight, the duration of their NPO (nothing by mouth) time, the expected length of the surgery, and the desired maintenance fluid rate in mL/kg/hr. ### Is Intra-Op Fluid Calculator suitable for all medical professionals? No, this app is specifically designed as a general-use fluid management reference for licensed Anesthesia providers. It is intended to support intraoperative planning and is not a substitute for formal training, institutional policies, or professional judgment. ### How often is Intra-Op Fluid Calculator updated? The developer continuously reviews published literature and local practices and will provide updates when changes are made. The latest version was updated on January 8, 2026. ### What devices is Intra-Op Fluid Calculator available on? Intra-Op Fluid Calculator is currently supported on iPhone devices. ### What is the price of Intra-Op Fluid Calculator? Intra-Op Fluid Calculator is a paid application, priced at $3.99. ### What is the age rating for Intra-Op Fluid Calculator? Intra-Op Fluid Calculator has an age rating of 17+, indicating it is intended for mature users. ## Version history (last 3 releases) ### 1.0.3 — 2026-01-08 updated App Icon for Liquid Glass. ### 1.0.2 — 2025-10-26 Minor update improving precision when adjusting intraoperative fluid loss values with the sliding scale. ### 1.0 — 2025-09-16 No release notes. ## Apps similar to Intra | App | Rating | Price | Category | | --- | --- | --- | --- | | [Qpath E Mobile](https://appshunter.io/ios/app/qpath-e-mobile/id1501398581) | 5.0 (1) | Free | Medical | | [Periop Pacemaker](https://appshunter.io/ios/app/periop-pacemaker/id6615070538) | 5.0 (7) | Free | Medical | | [C8 Health](https://appshunter.io/ios/app/c8-health/id1534264609) | 5.0 (2) | Free | Medical | | [myTIPreport](https://appshunter.io/ios/app/mytipreport/id999880046) | 4.0 (25) | Free | Medical | | [Stoelting Anesthetic Practice](https://appshunter.io/ios/app/stoelting-anesthetic-practice/id1201153756) | 5.0 (4) | Free | Medical | | [Lisa Safe](https://appshunter.io/ios/app/lisa-safe/id6504840087) | 5.0 (4) | Free | Medical | --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-07-18.*