Measure it. The three common sizes are visibly different and completely incompatible.
How to measure
Take the basket out and measure the internal diameter of the portafilter where the basket sits, with a ruler or callipers.
- 58 mm — the commercial standard. Gaggia, Lelit, Rancilio, ECM, Profitec, most prosumer machines.
- 54 mm — Sage and Breville.
- 51 mm — De’Longhi and various entry machines.
Confusingly, 58 mm baskets are not 58 mm
A “58 mm” basket has an internal diameter slightly over 58. That is why 58.5 mm tampers exist and fit better than nominal 58 mm ones — the extra half millimetre fills the basket properly instead of leaving a ring of loose coffee at the edge.
That ring is exactly where water escapes around the puck.
Dose ratings
Baskets are rated for a dose — 14, 18, 20, 22 g. Match the dose to the rating rather than to a number you read. Under-dosing leaves headroom; over-dosing chokes.
Precision baskets
IMS and VST make baskets with more consistent hole geometry than stock ones. They improve evenness and tighten the acceptable dose window, so weigh carefully.
Pressurised versus not
Check the underside: many small holes means single-wall. One hole behind a plate means pressurised.
Last reviewed 8 August 2026