Written and maintained by CASRAI Editorial Board
Last updated
General product information only, not medical advice. Choosing a tube for a patient is a clinical decision made by trained staff following the manufacturer’s instructions for use and local protocols.
Endotracheal tube sizes are labelled by internal diameter (ID) in millimetres, in 0.5 mm steps. The outside diameter (OD), length and cuff diameter at the same labelled size differ from one manufacturer to the next, so the chart below puts two manufacturers’ published figures side by side.
Endotracheal tube size chart
All values are taken from each manufacturer’s own product page, checked 2026-10-30. A dash means that product page does not list that size.
| ID (labelled size) | Shiley Hi-Lo cuffed | Rusch Safety Clear Plus cuffed | ||||
|---|---|---|---|---|---|---|
| OD | Length | Cuff diameter | OD | Length (without connector) | Cuff diameter | |
| 3.0 | 4.3 | 160 | 7.9 | – | – | – |
| 3.5 | 4.9 | 180 | 9.5 | – | – | – |
| 4.0 | 5.6 | 200 | 9.5 | – | – | – |
| 4.5 | 6.2 | 220 | 14.3 | – | – | – |
| 5.0 | 6.9 | 240 | 20.2 | 6.7 | 250 | 20 |
| 5.5 | 7.5 | 270 | 22.2 | 7.3 | 280 | 20 |
| 6.0 | 8.2 | 280 | 23.3 | 8.0 | 290 | 24 |
| 6.5 | 8.9 | 290 | 25.4 | 8.7 | 300 | 24 |
| 7.0 | 9.5 | 300 | 28.2 | 9.3 | 320 | 28 |
| 7.5 | 10.2 | 310 | 30.2 | 10.0 | 330 | 28 |
| 8.0 | 10.8 | 320 | 31.1 | 10.7 | 340 | 30 |
| 8.5 | 11.4 | 330 | 33.3 | 11.3 | 345 | 30 |
| 9.0 | 12.1 | 335 | 34.4 | 12.0 | 350 | 34 |
| 9.5 | 12.8 | 335 | 34.4 | 12.7 | 350 | 34 |
| 10.0 | 13.5 | 335 | 34.4 | 13.3 | 350 | 34 |
Sources: Medtronic (Shiley) cuffed basic endotracheal tubes product page; Teleflex Rusch Safety Clear Plus cuffed endotracheal tube (Murphy Eye) product page. Both pages list the tubes as not made with natural rubber latex. The Medtronic page describes them as sterile and offering infant, pediatric and adult options; the Teleflex page lists them as sterile and single-use. Check your product’s labelling: the figures printed on the package and instructions for use for the exact tube in your hand are the ones that apply.
How to read the chart
ID is the label
The first column is the size a tube is ordered and labelled by: the diameter of the inside of the tube. A 7.0 tube has a 7.0 mm internal diameter. Both manufacturers step in 0.5 mm increments; Shiley’s listed range runs from 3.0 to 10.0 mm and the Rusch Safety Clear Plus range listed here runs from 5.0 to 10.0 mm.
OD is the fit
The outside diameter is always larger than the ID because it includes the tube wall. It is the outer width of the tube. In the chart the OD runs from 1.3 to 3.5 mm above the ID, and the gap widens as tubes get larger.
Length and cuff diameter
Length is the overall tube length as the manufacturer states it (Rusch lists length without the connector). Cuff diameter is the width of the cuff measured by the manufacturer and is a product specification, not a target pressure or inflation value. This page gives no inflation guidance.
Why the same size differs by brand
Take a 7.0 mm ID tube. Shiley lists an OD of 9.5 mm, a length of 300 mm and a cuff diameter of 28.2 mm. Rusch lists 9.3 mm, 320 mm and 28 mm. At 7.5 mm the lengths are 310 mm and 330 mm. The label is the same; the tube is not. Treat any single chart, including this one, as a record of those products rather than a universal standard, and do not substitute one brand’s OD or length for another’s.
What is an endotracheal tube?
An endotracheal tube is a flexible tube placed through the mouth or nose into the trachea to keep an airway open. US federal regulation describes the broader device category, the tracheal tube (21 CFR 868.5730), as a device inserted into a patient’s trachea via the nose or mouth and used to maintain an open airway, and classifies it as Class II. The FDA classification database lists it under product code BTR and flags it as life-sustaining or life-supporting. Our guide what is an endotracheal tube covers the device in more detail.
Common mix-ups
- ID versus OD. A chart that lists a single number per size is almost always giving the ID. Confirm which diameter a table means before comparing it with another.
- Size versus length. Two tubes with the same ID can have different lengths, as the chart shows.
- Brand to brand. OD, length and cuff diameter at the same ID are not interchangeable between manufacturers.
- Different airway devices. Oral airways, laryngeal masks and stylets use their own sizing systems. See oral airway sizes, laryngeal mask airway sizes and stylets for endotracheal tubes rather than carrying numbers across.
Frequently asked questions
What do endotracheal tube sizes mean?
The size is the internal diameter in millimetres. In the products charted above it runs in 0.5 mm steps, for example 6.5, 7.0 and 7.5.
Is there a standard endotracheal tube size chart?
The charted manufacturers agree on the ID label but publish different ODs, lengths and cuff diameters. Use the chart from the manufacturer of the tube you are working with and its instructions for use.
What is an endotracheal tube?
A tube placed through the nose or mouth into the trachea to maintain an open airway; see the section above and our full guide. Related equipment includes the endotracheal tube holder.
Sources
- Medtronic, Shiley cuffed basic endotracheal tubes: product page, checked 2026-10-30.
- Teleflex, Rusch Safety Clear Plus cuffed endotracheal tube (Murphy Eye): product page, checked 2026-10-30.
- 21 CFR 868.5730, Tracheal tube: Cornell LII text, checked 2026-10-30.
- FDA product classification database, product code BTR, via openFDA, index last updated 2026-10-19, checked 2026-10-30.
