Laryngoscope blade size reference: Mac and Miller
Laryngoscope blade size is usually chosen by age, weight and anatomy. Published references generally list Miller 0 to 1 for newborns and infants, size 2 for young and school-age children, and size 3 from about age 10. One manufacturer describes its Mac 3 and Mac 4 blades as adult sizes. References differ at the edges, so this page shows each one side by side.
This is a reference, not a substitute for clinical judgment, your local protocol, or your medical director's direction. Blade choice depends on the patient in front of you, and published references don't always agree. Always have the next size up and down ready. Check the device's Instructions for Use for the blades it supports. I'm Andrew Napier, MD, the founder of IntuBlade Co., which makes Macintosh video laryngoscopes in sizes 1 to 4.
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Look up a published size
Choose an age band, a published weight, or a color zone. The tool shows each source as written. It does not interpolate between bands, and it does not pick a winner when sources disagree.
Lookup
Choose an age, weight or color zone.
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Full reference table
Every value below is copied from an opened source. On a phone, each row stacks into a card. The table stays in the page for screen readers, print, and search engines.
R1. Anesthesia Guide (Houck, 2013)
Houck PJ. Chapter 171. Pediatric Sizing Chart. In: Atchabahian A, Gupta R, eds. The Anesthesia Guide. McGraw-Hill; 2013. Opened 2026-11-09.
| Age or weight | Laryngoscope blade |
|---|---|
| 1 kg | Miller 00 |
| 2 kg | Miller 00 |
| 3 kg | Miller 0 |
| Term newborn | Miller 1 |
| 5 kg | Miller 1 |
| 1 year | Miller 1 |
| 2 to 9 years | Miller/Mac 2 |
| 10 to 18 years | Miller/Mac 3 |
R2. Merck Manual Professional Edition
Merck Manual Professional Edition. Table: Guide to Pediatric Resuscitation, Mechanical Measures (courtesy B. Paes and M. Sullivan, McMaster University). Opened 2026-11-09.
Merck's blade-style row switches at age 8. Younger columns say "Straight blade (preferred) or curved blade." Age 8 and older say "Curved or straight blade."
| Age (typical weight) | Laryngoscope blade | Blade style note |
|---|---|---|
| Term neonate (3.5 kg) | Miller 0 | Straight blade |
| Under 12 months (under 10 kg) | 1 | Straight blade (preferred) or curved blade |
| 1 year (10 kg) | 1 | Straight blade (preferred) or curved blade |
| 2 years (12 kg) | 1 | Straight blade (preferred) or curved blade |
| 3 to 7 years (14 to 22 kg) | 2 | Straight blade (preferred) or curved blade |
| 8 to 9 years (25 to 28 kg) | 2 | Curved or straight blade |
| 10 to 16 years (30 to 60 kg) | 3 | Curved or straight blade |
R3. Florida EMSC poster (Final 09.24.2024)
Florida EMSC, "Pediatric Emergency ABCs and More" poster (Final 09.24.2024), Airway Equipment table. Educational and informational purposes only. Opened 2026-11-09.
| Zone | Weight (kg) | Age estimate | L-scope blade |
|---|---|---|---|
| Grey, 3 kg | 3 | under 3 mo | 1 straight |
| Grey, 4 kg | 4 | under 3 mo | 1 straight |
| Grey, 5 kg | 5 | under 3 mo | 1 straight |
| Pink, 6 to 7 kg | 6 to 7 | 3 to 5 mo | 1 straight |
| Red, 8 to 9 kg | 8 to 9 | 6 to 11 mo | 1 straight |
| Purple, 10 to 11 kg | 10 to 11 | 12 to 24 mo | 1 straight |
| Yellow, 12 to 14 kg | 12 to 14 | 2 yrs | 2 straight/curved |
| White, 15 to 18 kg | 15 to 18 | 3 to 4 yrs | 2 straight/curved |
| Blue, 19 to 23 kg | 19 to 23 | 5 to 6 yrs | 2 straight/curved |
| Orange, 24 to 29 kg | 24 to 29 | 7 to 9 yrs | 2 to 3 straight/curved |
| Green, 30 to 36 kg | 30 to 36 | 10 to 11 yrs | 2 to 3 straight/curved |
R4. Medtronic McGRATH MAC (manufacturer)
Medtronic, McGRATH MAC video laryngoscope page. Manufacturer description of its own blades, not a clinical guideline. Opened 2026-11-09.
manufacturer description
| Band | Laryngoscope blade | Notes |
|---|---|---|
| Adult | Mac 3 and Mac 4 | McGRATH MAC blades size 1 and 2 are for smaller patients. Size 3 and 4 are for adult patients. |
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Mac vs Miller in one minute
Many clinicians prefer a straight Miller blade in infants and young children because the larynx sits higher and the epiglottis is longer. OpenAnesthesia notes that straight blades are often preferred under 2 years, and that studies have not shown a statistical difference in intubation success between curved and straight blades. A Macintosh blade lifts the epiglottis indirectly via the vallecula. NICE describes the common blade families as Macintosh curved, angulated, and Miller straight. Choose the blade your protocol and device support.
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Why references differ
These charts were built for different jobs. Houck's Anesthesia Guide chapter is a pediatric sizing chart. The Merck table is a pediatric resuscitation equipment guide. The Florida EMSC poster is a color-zone airway equipment list. The Medtronic page describes McGRATH MAC blades, not a clinical guideline. Editorial cutoffs differ at the edges, including term newborns, 2 years, and the move from size 2 to size 3. This page shows each source. It does not pick a winner. Follow your local protocol and medical director.
- Term newborn: Miller 0 (R2) vs Miller 1 (R1).
- 3 kg: Miller 0 (R1) vs 1 straight (R3).
- 2 years: 1 (R2) vs Miller/Mac 2 (R1) vs 2 straight/curved (R3 Yellow).
- 7 to 11 years: 2 (R1, R2 through 9 years) vs 2 to 3 (R3 Orange/Green). R1 and R2 move to 3 at 10 years.
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Video laryngoscope blade sizes are device-specific
Video laryngoscope blade sizes are device-specific. A size 3 Macintosh on one device is not automatically the same length or geometry as a size 3 on another. Check every blade family your device supports in that manufacturer's Instructions for Use. IntuBlade product names are Macintosh Size 1, Macintosh Size 2, Macintosh Size 3, and Macintosh Size 4.
See IntuBlade Macintosh sizes 1 to 4 and the EMS video laryngoscope comparison.
Common questions
What size Mac blade is used for adults?
Medtronic describes its McGRATH Mac 3 and Mac 4 blades as adult sizes. Choose based on the patient and your protocol.
What laryngoscope blade size is used for a newborn?
Published references list Miller 0 or Miller 1 for a term newborn, and Miller 00 for very small preterm infants. Check your local neonatal protocol.
When do references switch from size 2 to size 3?
Two references switch at about 10 years. A color-zone reference lists 2 to 3 from about 7 years.
Mac or Miller for children?
Many clinicians prefer a straight blade in infants and young children. A curved blade is common in older children. Both can work when used correctly.
What sizes does IntuBlade come in?
IntuBlade comes in Macintosh Sizes 1, 2, 3 and 4. It does not come in Miller or size 0.
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Sources
Last clinically reviewed by Andrew Napier, MD, FAAEM, board-certified in emergency medicine on 9 November 2026.
- R1 Houck PJ. Chapter 171. Pediatric Sizing Chart. In: Atchabahian A, Gupta R, eds. The Anesthesia Guide. McGraw-Hill; 2013. Opened 2026-11-09.
- R2 Merck Manual Professional Edition. Table: Guide to Pediatric Resuscitation, Mechanical Measures (courtesy B. Paes and M. Sullivan, McMaster University). Opened 2026-11-09.
- R3 Florida EMSC, "Pediatric Emergency ABCs and More" poster (Final 09.24.2024), Airway Equipment table. Educational and informational purposes only. Opened 2026-11-09.
- R4 Medtronic, McGRATH MAC video laryngoscope page. Manufacturer description of its own blades, not a clinical guideline. Opened 2026-11-09.
Supporting explainer sources, not table values:
- OpenAnesthesia, Raza SA, Pediatric Direct Laryngoscopy and Tracheal Intubation (updated 04/04/2023). Mac vs Miller explainer only. Its Coté age table was not transcribed.
- NICE MIB167, The technology. Blade families: Macintosh curved, angulated, Miller straight.