ETT Size Calculator (Pediatric)
The ETT Size Calculator estimates the endotracheal tube size and insertion depth for a child from age, using standard formulas. For clinical education only.
Rates and fees change frequently. Always confirm the current figures
with the official authority before relying on this result.
Formula
Uncuffed ID = age/4 + 4; Cuffed ID = age/4 + 3.5; Depth = age/4 + 12
- These formulas apply to children over about 1–2 years of age.
- Always confirm tube position clinically and with imaging.
4-year-old
Inputs
- Age: 4 years
Cuffed 4.5 mm, uncuffed 5.0 mm, depth 13 cm.
Frequently asked questions
How is pediatric ETT size estimated?
By age-based formulas: uncuffed internal diameter ≈ age/4 + 4 mm, cuffed ≈ age/4 + 3.5 mm.