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General product information only, not medical advice. A clinician chooses and fits the tube for each patient. Always check your product’s own labelling and instructions for use (IFU).
A gastrostomy tube size is not one number. For a low-profile button it is a French (Fr) diameter, a stoma length in centimetres and a balloon fill volume in mL; for a PEG kit it is the Fr size listed on the kit. The chart below puts three manufacturer documents side by side so you can see what each maker publishes, and why a chart from one brand cannot be reused for another. For how a button is built and what comes in a kit, see the G-tube button guide; for tube families, see G-tube types.
Gastrostomy tube sizes: the chart
Balloon volumes are the manufacturers’ published values for their own buttons. A dash means the manufacturer’s document does not list that size.
| French size | About mm (Fr × 0.33) | Compat Buddy balloon mL: recommended (max) | AMT G-JET balloon mL: recommended (min to max) | Boston Scientific PEG kit listing |
|---|---|---|---|---|
| 12 Fr | 4.0 | 3.0 (5.0) | – | – |
| 14 Fr | 4.6 | 4.0 (6.0) | 4 (3 to 5) | – |
| 16 Fr | 5.3 | 5.0 (7.0) | 4 (3 to 5) | – |
| 18 Fr | 5.9 | 5.0 (7.0) | 8 (7 to 9) | – |
| 20 Fr | 6.6 | 8.0 (12.0) | – | Listed (pull or push) |
| 24 Fr | 7.9 | 8.0 (12.0) | – | Listed (pull or push) |
Sources: Compat Buddy datasheet AXI00044 Rev. 3 (April 2024); Applied Medical Technology (AMT) G-JET Button brochure C-4497-M (2025); Boston Scientific standard PEG kit product page. Links and dates are in the Sources section below. The millimetre column uses the general convention of about one third of a millimetre per French unit, rounded to one decimal; it is not a manufacturer specification.
How to read a size
A low-profile button is described by three values, and all three matter when ordering.
| Family | What the size consists of | Range published by the manufacturer |
|---|---|---|
| Balloon gastric button (Compat Buddy) | French size + stoma tract length + balloon volume | 12, 14, 16, 18, 20 and 24 Fr; lengths 0.8 to 6.5 cm |
| Gastric-jejunal button (AMT G-JET) | French size + stoma length + balloon volume + jejunal tube length | 14, 16 and 18 Fr; stoma lengths 1.0 to 6.0 cm; jejunal lengths 15, 22, 30 and 45 cm (availability varies by size and stoma length) |
| PEG kit (Boston Scientific) | French size on the kit, pull or push placement type, round or T-bar external bolster | 20 and 24 Fr listed |
So “18 Fr 1.5 cm” means a button 18 Fr in diameter for a stoma tract 1.5 cm long. Compat prints the French size and length on the button’s cap and the balloon volume in mL on the inflation valve; AMT states the recommended water volume is printed on the fill valve.
What decides the length
The length column is the part buyers most often miss. AMT states that a proper fit depends on measuring the stoma length with its own Balloon Stoma Measuring Device, so the measurement is made by the care team with the manufacturer’s tool, not estimated from a chart. The Compat ordering tables list stoma lengths from 0.8 cm in steps up to 5.5 cm for every size, with 6.0 and 6.5 cm offered only for some sizes (14 and 18 Fr among them).
Equivalence notes: Fr, millimetres and balloon volume
- Fr to mm. The French scale is a diameter measure at about 0.33 mm per unit, so 12 Fr is about 4 mm. The NG tube size chart shows the same convention with its sources.
- Balloon mL is not transferable. At 18 Fr, Compat recommends 5.0 mL and AMT recommends 8 mL. At 14 Fr both recommend 4 mL. The volume printed on each product is the one that applies to it, and AMT directs readers to consult their healthcare provider about any change.
Common mix-ups
- Diameter versus length. Same Fr size, different stoma length are different products.
- Kit contents. Compat’s Buddy Kit holds the button, two ENFit extension sets, a 35 mL ENFit syringe, a 10 mL Luer syringe, a stylet, water-soluble lubricant and two gauze pads. Its Compact Kit has the button, the 10 mL Luer syringe, stylet, lubricant and gauze but no extension sets.
- Connector type. The balloon is filled through a Luer valve, while feeding sets may be ENFit. See G-tube suppliers and product listings.
- Cutting. AMT notes that G-JET devices should never be cut to custom lengths.
- Two ports. On a G-J button, AMT states different feed or extension sets are required for each port.
What is a GJ tube for adults?
A GJ (gastric-jejunal) tube has separate gastric and jejunal ports. The AMT G-JET adds a jejunal tube of 15, 22, 30 or 45 cm to the button sizes in the chart. The manufacturer documents cited here do not define an age-specific size, so the choice of device belongs to the care team. For the clinical contrast with a standard G-tube, read GJ tube vs G-tube.
Check your product’s labelling
Before using or ordering, compare the Fr size, stoma length, balloon volume and connector type printed on the product and its IFU with the order. Compat’s datasheet itself says it does not replace the original IFU, and Boston Scientific directs readers to the package insert for the complete indications for use.
FAQ
What are the sizes of PEG tubes?
The Boston Scientific standard PEG kit page lists 20 Fr and 24 Fr, in pull and push versions. Other makers list other sizes; read the package insert.
What gastrostomy tube sizes do buttons come in?
Compat lists 12 to 24 Fr in six sizes; AMT’s G-JET lists 14, 16 and 18 Fr.
How is a gastrostomy tube size written?
As a French size, often with a stoma length, such as 18 Fr 1.5 cm, plus a balloon volume in mL for balloon buttons.
What is a feeding tube?
See what a feeding tube is for the plain-language overview.
Sources
- Compat, “Full Range of Low-profile Gastrostomy Feeding Tubes” (Buddy), datasheet AXI00044 Rev. 3, 18 April 2024: compat.com. Date checked: 2026-11-01.
- Applied Medical Technology, G-JET Button brochure C-4497-M (2025): appliedmedical.net. Date checked: 2026-11-01.
- Boston Scientific, EndoVive standard PEG kit: bostonscientific.com. Date checked: 2026-11-01.
