Pediatric ETT Size Calculator
Compute the recommended pediatric endotracheal tube size and insertion depth for a given age.
Open the calculator → Runs in your browser. Data leaves only if you deliberately send a problem report from the interactive tool.
Example
- Patient age
- 4 years
- Tube type
- Uncuffed (age/4 + 4)
Result: Tube 5.0 mm uncuffed, depth 15 cm.
The tool opens with these values already filled in. Replace them with your own.
What you enter
- Patient age
- Tube type
What this is
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.
How this is calculated
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.
A reference and educational tool. Not medical, legal, or financial advice, and not a substitute for clinician judgment.
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