FiO2 Calculator

Quick FiO2 calculator for nasal cannula, face mask, and NRBM oxygen therapy flow. Choose flow rate and see estimated FiO2 %.

FiO2 Calculator is a simple, fast reference tool for estimating fraction of inspired oxygen (FiO2) based on oxygen flow rate. Select a delivery device from Nasal Cannula, Face Mask, or Non-Rebreather Mask (NRBM) and adjust the flow rate slider to see the estimated FiO2 percentage update instantly on a clear, easy-to-read gauge. Features: • Three oxygen delivery devices with device-appropriate flow ranges • Instant FiO2 percentage estimate as you adjust flow rate • Low-flow safety alerts (e.g. CO2 rebreathing risk on face mask below 5 LPM) • Step-up suggestions when a device reaches its maximum flow rate • Quick-access links to clinical references (Medscape, Geeky Medics, Open Critical Care) For clinical reference only. This app is a quick-estimate tool and is not a substitute for professional clinical judgment, hospital protocol, or medical training.