Endotracheal Tube Size Calculator
Calculate optimal ETT size and insertion depth for safe intubation
Calculate ETT Size
CRITICAL MEDICAL DISCLAIMER
This calculator is for educational purposes ONLY and should NEVER replace clinical judgment.
- Always have multiple ETT sizes available (±0.5mm)
- Verify tube placement with multiple methods
- Only trained medical professionals should perform intubation
- Patient anatomy may require different sizing
Age-based (standard method)
Age + height + weight based
Primary parameter for ETT sizing
Required for Eck's formula
Required for Eck's formula
ETT Size Results
Patient Category: Preterm/Newborn
Formula used: Cole's Formula
Age: 0.0 years
Example Calculations
5-Year-Old Child (Cole's Formula)
Age: 5 years
Uncuffed ETT: (5 ÷ 4) + 4 = 5.25 mm
Cuffed ETT: (5 ÷ 4) + 3 = 4.25 mm
Insertion depth: (5 ÷ 2) + 12 = 14.5 cm
Adult Patient
Standard sizes:
• Female: 7.0-7.5 mm cuffed
• Male: 8.0-8.5 mm cuffed
• Always have ±0.5mm sizes available
ETT Size Guidelines
Newborn
2.5-3.0 mm uncuffed
Preterm: 2.5mm, Term: 3.0mm
Pediatric
Cole's formula
Age-based sizing 1-12 years
Adult
7.0-8.5 mm cuffed
Female: 7.0-7.5, Male: 8.0-8.5
Intubation Safety
Have multiple ETT sizes ready (±0.5mm)
Verify tube placement with capnography
Auscultate bilateral breath sounds
Check chest X-ray for tube position
Monitor cuff pressure (20-30 cmH₂O)
Remember: Clinical judgment always supersedes calculator recommendations.
Understanding Endotracheal Intubation
What is Endotracheal Intubation?
Endotracheal intubation is a critical medical procedure where a plastic tube (ETT) is inserted into the trachea to maintain an airway, deliver mechanical ventilation, and protect against aspiration during anesthesia or critical care.
Why Size Matters
- •Too large: Trauma, vocal cord damage, difficult insertion
- •Too small: Air leak, inadequate ventilation, tube displacement
- •Proper size: Secure airway, effective ventilation, minimal complications
Calculation Methods
Cole's Formula (Standard)
Uncuffed = (Age ÷ 4) + 4
Cuffed = (Age ÷ 4) + 3
For children 1-12 years
Eck's Formula (Advanced)
2.44 + (Age × 0.1) + (Height × 0.02) + (Weight × 0.016)
Considers multiple patient factors
Clinical Note: Always verify tube placement with multiple methods including capnography, auscultation, and chest X-ray. Have backup equipment ready.
Age-Specific Considerations
Neonates & Infants
- • Prefer uncuffed tubes
- • Smaller larynx, more anterior
- • Higher metabolic demands
- • Risk of subglottic stenosis
- • Weight-based calculations
Pediatric (1-8 years)
- • Cole's formula most accurate
- • Both cuffed/uncuffed acceptable
- • Rapid desaturation risk
- • Cricoid ring narrowest point
- • Have multiple sizes ready
Adults (>8 years)
- • Cuffed tubes standard
- • Gender differences in sizing
- • Anatomy more predictable
- • Lower complication rates
- • Alternative sizing methods