Basket size is two different numbers: the diameter that must fit your portafilter and the dose capacity that decides how much coffee you can use. Mixing either up wrecks your shots and your parts budget.
Diameter for fit, dose rating for capacity: two numbers, one basket.The Direct Answer: Two Numbers Matter
The diameter (measured across the inside of the basket) must match your portafilter and group, with 58 mm the professional standard and 54 mm common on home machines. The dose capacity is separate: an 18 g basket holds about 18 g comfortably, a 20 g basket about 20 g. Use the diameter to buy the right parts and the dose rating to pick your recipe; they are independent.
Standard Sizes at a Glance
| Diameter | Where you see it | Typical dose capacity |
|---|---|---|
| 51 mm | Some compact machines | 12-16 g |
| 54 mm | Common home machines | 14-18 g |
| 58 mm | Professional standard | 18-20 g+ |
| 58.5 mm | Some pro baskets | 18-22 g |
Within a diameter you may find single, double, and triple baskets with different depths; the dose rating on the basket is your guide.
What "18g" and "20g" Mean
The number is a dose guidance, not a legal limit. An 18 g basket is designed for about 16-19 g, a 20 g basket for about 18-22 g, and the "right" dose sits where the puck fills the basket without touching the shower screen and without leaving a large gap. Dosing far outside the rating produces the two classic failures: too low gives a fast, soupy shot; too high chokes the machine and can jam the portafilter.
How to Measure Yours
Find your basket size in two minutes:
- Remove the basket from the portafilter.
- Look for a stamp with numbers on the side or underside.
- If there is no stamp, measure the inner diameter with a ruler or caliper.
- Compare both the diameter and the dose number against the manual.
When in doubt, measure: home machines look similar and 54 mm versus 58 mm is a four-millimeter difference that fits nothing interchangeably.
Measure the inside of the basket; the outside is not the number that matters.Choosing a New Basket
When upgrading, match the diameter to the machine, then choose the dose by your routine. Want standard doubles? Pick an 18 g double basket. Want stronger shots or bigger cups? Consider a 20 g basket, but check that your grinder and technique can feed it. Precision baskets with straight walls and no taper are popular for consistency, but they reward good puck prep; start with a well-made basket that matches your skill level.
Edge Cases and What to Try Next
If your puck always shows the shower screen imprint, the dose is too high for the basket; reduce it or move up a basket size. If the shot always gushes with a correct grind, the dose may be too low; increase toward the basket rating. If you bought accessories that looked right but do not fit, check the diameter again; a 54 mm tamper in a 58 mm basket is the classic mistake. Each fix starts with reading the numbers on the basket you actually own.
Authoritative Sources
Independent references for the basket sizing and selection guidance in this guide.
FAQ
What is the standard size portafilter basket for espresso machines?
The most common standard sizes are 54 mm and 58 mm in diameter, with 58 mm the professional standard and 54 mm common on home machines. Dose capacity is separate: 54 mm baskets often hold 14-18 g, while 58 mm baskets commonly hold 18-20 g or more.
What are the standard sizes of portafilter baskets?
Common portafilter basket diameters are 51 mm, 54 mm, 58 mm, and 58.5 mm. Dose capacity varies within a diameter, from single and double to triple baskets. Match both the diameter and the dose rating to your machine and portafilter.
Is Breville 54mm or 58mm?
Most Breville home espresso machines use a 54 mm portafilter, while the professional-standard size is 58 mm. Check your specific model and basket stamp, because accessories from one size do not fit the other.
How do I know what size portafilter basket I have?
Measure the inner diameter of the basket with a ruler or caliper, or check the stamp and the manual. Common sizes are 51, 54, and 58 mm. If your current basket is not stamped, measure; a quarter-inch error sends you to the wrong parts.
Matching the basket to the machine? See the Meraki basket and accessory collection, or check the machine page for the included basket size.
Basket sizes and doses are general espresso practice, not Meraki-specific claims. The included basket and its rating follow the official product page.
