Correctly sized, an espresso tamper should be slightly smaller than the inside diameter of your espresso machine filter basket to insure complete compaction of the ground coffee without binding. The best method to identify correct tamper size is to measure the exact inside diameter of your filter basket using machinist calipers then select a tamper slightly smaller than this measurement. In the event that you do not have access to a set of calipers take the needed measurement it is possible to use a steel measuring tape with 1/32" divisions and a very careful eye and steady hand to take the measurement and convert to millimeters as follows:

1. measure the largest distance inside the filter basket across the centerline
2. convert the measurement to decimal units
3. multiply inches by 25.4 to convert to millimeters
4. select a tamper slightly smaller (at least 0.75 mm for clearance) than your filter basket measurement

Example:

1. using a steel tape you determine the inside diameter of your filter basket measures 2-10/32"
2. convert to decimal units: 10/32 + 2 = 2.3125"
3. convert to millimeters: 2.3125" x 25.4 = 58.74mm
4. the tamper that you like is available in sizes 49mm, 53mm and 58mm; therefore, the best fit would be 58mm

In addition, Espresso Zone has complied a list as follows for many popular espresso machines to assist with your selection. However, please note that actual measurement of your filter basket is always the most reliable method; we cannot guarantee size compatibility as sometimes variations are made by manufacturers within a given model or based on the year the machine was manufactured. The following list is accurate for the current model machines that Espresso Zone carries. Please feel free to call us if there is any question as we would be happy to assist with sizing.