Oral tube depth (cm at lips) = age/2 + 12 for children ≥ 2 years (≈ 3 × ETT ID).
years
Oral depth at lips
15.0 cm
Formula
age / 2 + 12
Notes
Nasal tube: age/2 + 15. Always confirm with capnography, auscultation and chest X-ray (tip at T2-T3).References
Calculators support, not replace, clinical judgement. Check inputs and units, and confirm doses with your unit protocol.