Endotracheal Tube — Age / NTL+1
The ETT Size and Depth Calculator brings together several independent bedside methods for choosing an endotracheal tube's internal diameter and oral insertion depth in neonates and children. Tube size can be estimated by neonatal weight band or by the age-based Cole formula, while insertion depth can be derived from nasal-tragus length (NTL), weight, age, or tube diameter as a cross-check. Each method in the app is self-contained so a clinician can use whichever inputs are available at the bedside, with a built-in reference table for common newborn weight bands.
The app labels NTL + 1 cm (nasal-tragus length plus 1 cm) as the preferred neonatal method.
The Cole formula — uncuffed internal diameter = (age/4) + 4, with a cuffed variant of (age/4) + 3.5 for children 2 years and older.
The app's checklist calls for equal bilateral chest rise and breath sounds, a CO2 trace, listening over both axillae and the stomach, and a CXR showing the tip between T1–T2; if right-mainstem intubation is suspected, pull back 1 cm and reassess.
2.5 mm uncuffed, per the app's neonatal weight-band table.
Yes — 3 × the tube's internal diameter is offered in the app as a universal cross-check against the other depth methods.