ETT size chart by age with pediatric starting formulas, depth-at-lip shortcuts, airway-adjunct sizing, and laryngoscope blade anchors for anesthesia review.
Review the core table first, then launch practice to convert recognition into faster recall.
These numbers are starting anchors, not substitutes for bedside confirmation of leak, resistance, depth, and patient anatomy.
| Age or clinical context | ETT ID uncuffed (mm) | ETT ID cuffed (mm) | Depth at lip | Blade size |
|---|---|---|---|---|
| Preterm infant | 2.5-3.0 uncuffed | 2.5-3.0 cuffed | 8-10 cm | Miller 0 |
| Term infant | 3.0-3.5 uncuffed | 3.0-3.5 cuffed | 9-11 cm | Miller 1 |
| 1 year | 4.25 uncuffed | 3.75-4.0 cuffed | ≈12 cm | Miller 1 |
| 4 years | 5.0 uncuffed | 4.5 cuffed | ≈15 cm | Miller 2 |
| 8 years | 6.0 uncuffed | 5.5 cuffed | ≈18 cm | Mac 2 or 3 |
| Average adult | 7.0-7.5 female / 7.5-8.0 male | same starting range | 21-23 cm | Mac 3 |
| Large adult | 8.0-8.5 | same starting range | 23-24 cm | Mac 4 |
| Topic | Rule |
|---|---|
| Uncuffed pediatric ETT | Age/4 + 4 mm |
| Cuffed pediatric ETT | Age/4 + 3.5 mm |
| Depth at lip | ≈ 3 × ETT ID (mm) |
| OPA sizing | Corner of mouth to angle of mandible |
| NPA sizing | Nares to tragus or angle of mandible |
This tool is for educational purposes only. Always verify clinical values against current authoritative sources before patient care.