Pediatric Endotracheal Tube (ETT) Size
Age-based inner diameter estimates (mm); many services use length/depth charts as well.
Calculator
How it works
What this tool does
Provides commonly taught estimates: uncuffed ID ≈ (age/4)+4 mm; cuffed ID ≈ (age/4)+3.5 mm for older teaching variants—confirm against your reference card.
Formulas (teaching)
Uncuffed inner diameter (mm) ≈ (age in years / 4) + 4 Cuffed inner diameter (mm) ≈ (age in years / 4) + 3.5
Cautions
Does not output tube depth at lips/nose, suction catheter size, or blade selection. Age 0 yields small IDs—many teams prefer weight-based or specialty neonatal rules.
Educational tool only—not for diagnosis or treatment decisions.