I'm looking for the diameter of the connection point for both the clarinet and bass clarinet. The part in red below.

enter image description here

  • 1
    Different models of clarinets have different dimensions. There is no "universal standard size" either for the tenon (the external diameter) or the bore (internal diameter).
    – user19146
    Nov 23, 2016 at 23:29
  • @alephzero: Despite its brevity this should be an answer.
    – guidot
    Nov 30, 2016 at 8:01

3 Answers 3


My research indicates that there are two standard sizes:

"The diameter of the bore is defined by the instrument (or better: its type), because the mouthpiece must have the same bore as the rest of the instrument. This is for example 15,2 mm (equals 0.598 inch) for a German style A- or B flat clarinet and it is 14,9 mm (equals 0.587 inch) for an A or B flat Boehm instrument, just below the mouthpiece."


(It is highly likely that if you aren't in Germany, you will be using a Boehm instrument.)

Further evidence for there being a standard fitting comes from various suppliers' online shops, where a range of clarinet mouthpieces are offered with no mention of different sizes.

I will be able to consult a clarinet player on the subject later today!


As has been commented, the diameter of the mouthpiece connection point will change from brand to brand and model to model.

  • I'd love to view a chart of all of the brands / models of clarinets and their sizes. Or at least an average. Nov 30, 2016 at 19:01
  • @ThomasReggi There is way too much variation between sizes, it would be very hard to create a chart
    – aimorris
    Nov 30, 2016 at 19:12

Laurence Payne gave the inner diameter numbers. In your image it looks like you're looking for the outer diameter.

I'm measuring my B45 (Bb clarinet) and EPE JM (Bb bass clarinet) mouthpieces with a simple ruler, so I can't give a sub-1mm accuracy. I'm reading 22mm and 30mm respectively. For comparison, the inner diameters are 15mm and 23mm.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.