
Free
About
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.
Show more
What's New in FiO2 Calculator
1.0
July 14, 2026