Written and maintained by CASRAI Editorial Board
Last updated
General product information only, not medical advice. Choosing a blade for a particular patient is a clinical decision for a trained clinician. Always check your product’s labelling and instructions for use.
Macintosh laryngoscope blades are made in sizes 0 to 4. In one humanitarian supplier’s catalogue, size 0 is described as newborn, 1 as baby, 2 as child, 3 as adult small and 4 as adult large, with lengths from 55 mm to 130 mm. The chart below lists those figures, and explains why the same size number can mean a different length from another manufacturer.
Macintosh blade size chart
Source: International Red Cross item catalogue, laryngoscope entry (checked 2026-10-30). The catalogue lists these as “length with blade”, and its descriptors are its own product labels, not an international standard.
| Macintosh size | Catalogue descriptor | Length with blade (catalogue) | Handle set listed |
|---|---|---|---|
| 0 | Newborn | 55 mm | 19 mm handle set |
| 1 | Baby | 70 mm | 19 mm handle set |
| 2 | Child | 90 mm | 19 mm and 28 mm handle sets |
| 3 | Adult small | 110 mm | 28 mm handle set |
| 4 | Adult large | 130 mm | 28 mm handle set |
Paediatric sizes (0 to 2)
Sizes 0, 1 and 2 are the paediatric end of the range in the catalogue: newborn, baby and child. Size 2 appears in both the 19 mm and the 28 mm handle sets with the same 90 mm figure, so it is the one size that overlaps the smaller and larger handle systems in that catalogue. The catalogue gives no age or weight ranges, and this page does not either.
A second manufacturer for comparison
ALIMED’s listing for the Welch Allyn English Macintosh blade (checked 2026-10-30) offers sizes 1 and 3 and gives the length from base to tip as 70 mm for size 1 and 110 mm for size 3. Those match the catalogue figures above, although the two sources word the measurement differently (“length with blade” and “length from base to tip”), which is why the next section matters.
How to read the chart
A size number is a label from the maker, not a physical unit. Three things change what the number means.
- What is measured. The Red Cross catalogue says “length with blade”. ALIMED says “length from base to tip”. Other makers may state a different measurement again, so the same blade can have different published figures.
- Who made it. Figures are specific to a product line. Compare lengths only between products that state the same measurement.
- Handle system. The catalogue lists blades for two handle diameters, 19 mm and 28 mm. A blade fits a handle designed for its fitting, so a size number alone does not tell you a blade will fit your handle.
Macintosh vs Miller, and other laryngoscope blade sizes
The same catalogue defines two blade types. A Macintosh blade is a slightly curved blade with a small bulbous tip, fixed to a hook-on handle. A Miller blade is a straight blade with a curved atraumatic tip and a flat, narrow flange. The catalogue lists Miller blades as no. 0 (newborn) and no. 1 (baby) and gives no Miller lengths, so this page does not give them either. For Miller blade sizes, use the length stated in the manufacturer’s own documentation.
For the instrument as a whole, see what a laryngoscope is. For the tube that is placed with it, see what an endotracheal tube is.
What the standard does and does not set
ISO 7376:2020, “Anaesthetic and respiratory equipment: Laryngoscopes for tracheal intubation” (edition 3, August 2020), specifies critical dimensions for handles and laryngoscope blades with interchangeable hook-on fittings. Its published scope describes fitting dimensions. The public catalogue page does not list blade size numbers or lengths, so nothing on this page is attributed to the standard. Two blades that both claim hook-on compatibility can still differ in length for the same size number.
Common mix-ups
- Treating size 3 as a fixed 110 mm. Two sources above give 110 mm, but they word the measurement differently and other makers may publish other numbers.
- Mixing up Macintosh and Miller numbers. Both types use small numbers such as 0 and 1, but one is curved and the other straight.
- Assuming the blade fits any handle. Handle diameter and fitting type are separate from blade size.
- Reading a descriptor as a rule. “Adult small” is a product label, not a clinical selection rule.
Reusable blades fall under device reprocessing rules; see medical device reprocessing. For how device records identify a product by size, see UDI for medical devices, and for the regulatory category, what a medical device is.
Frequently asked questions
What sizes do Macintosh laryngoscope blades come in?
The Red Cross catalogue lists Macintosh blades in sizes 0 to 4, from newborn to adult large. Other makers may offer a subset, for example sizes 1 and 3 in the ALIMED listing.
What are the laryngoscope blade sizes?
Laryngoscope blades are sized by type. Macintosh runs 0 to 4 in the catalogue above. Miller is listed as 0 and 1 in the same catalogue. Check the length in your own product’s documentation.
What are Miller blade sizes?
The catalogue lists Miller no. 0 (newborn) and no. 1 (baby), each described as reusable. It gives no lengths, so use the manufacturer’s instructions for use for dimensions.
Is a size 3 the same length from every manufacturer?
Not necessarily. Two sources here give 110 mm, but they word the measurement differently, and other manufacturers may publish different figures. Check your product’s labelling.
Sources
- International Red Cross item catalogue, laryngoscope: https://itemscatalogue.redcross.int/health–3/medical-equipment–15/anaesthesia–4/laryngoscope–XANELARY.aspx (checked 2026-10-30).
- ALIMED, English Macintosh laryngoscope blades (Welch Allyn): https://www.alimed.com/english-macintosh-laryngoscope-blades.html (checked 2026-10-30).
- ISO 7376:2020, catalogue page: https://committee.iso.org/standard/71539.html (checked 2026-10-30).
