Pediatric ETT Size Calculator
Pediatric ETT Size Calculator - a deterministic tool in Sophie Well's EMS & Field Medicine group.
Open the Pediatric ETT Size Calculator → Runs in your browser. No signup, no tracking.
What this is
Compute the recommended pediatric endotracheal tube size and insertion depth for a given age. The standard formulas are cuffed ETT size (mm internal diameter) = age/4 + 3.5, uncuffed = age/4 + 4, and depth at the lip (cm) = 3 times the tube size. Sophie Well takes the patient age and returns the cuffed and uncuffed size suggestions along with the suggested depth, the appropriate laryngoscope blade size, and the half-size above and below to have ready for the airway tray.
When to use it
Use this when preparing to intubate a pediatric patient and you need a fast estimate before reaching the bedside, when assembling an airway kit for transport, or when teaching a learner the canonical formulas. These are reference values - actual size selection is verified by leak test at the cuff (or appropriate fit for uncuffed) and by clinical assessment of the patient's anatomy, and a length-based resuscitation tape (Broselow) remains the recommended bedside reference for code situations. The formulas underestimate in children with airway anomalies and oversimplify above adolescence.
References
Cuffed: age/4 + 3.5 mm. Uncuffed: age/4 + 4 mm. Depth at the lip = 3 x tube size in cm. Standard pediatric airway formulas; verify against bedside assessment.
Worked example: Tube 5.0 mm uncuffed, depth 15 cm.
Sophie Well is a reference and educational tool. Not medical, legal, or financial advice. Does not replace clinician judgment, professional billing review, or legal counsel.