By the name of the hotend, not by the thread alone. Nozzles follow hotend families that differ in thread, length and shape, and many recent printers use a proprietary quick-change nozzle; the printer maker’s manual or spare-parts page names the one it takes.
A nozzle looks like a generic brass part, and that appearance is exactly why so many are bought for the wrong printer.
The three things that must match
The hotend family. Nozzles are made for a hotend design, and the listing should name it or name the printers it fits. The thread and length, which follow from that family: a nozzle can share a thread with another design and still be a different length. The shape of the body, which on quick-change systems is the whole fitting — these nozzles are not screwed in at all, and only the maker’s own part or a part sold explicitly for that printer fits.
Where to find the answer
The printer’s manual and the maker’s spare-parts listings name the nozzle type. Third-party listings that name specific printer models are more useful than listings that give only a thread size. When a printer has been modified with a different hotend, the hotend’s own name decides, not the printer’s.
What can be chosen freely
The orifice diameter can move up or down, with a matching change in the slicer. The material can change too: hardened steel or tipped nozzles resist the abrasive filaments that wear brass quickly, and they are sold in the same hotend families.
How a nozzle is changed
Hot, with the maker’s procedure. Nozzles are usually tightened at printing temperature so that the seal holds when the metal expands, and the printer manual gives the temperature and the torque advice where it exists.
Questions makers ask before buying
Why does a nozzle with the right thread still leak?
Because the length can differ between two nozzles with the same thread. A nozzle that is too short or too long changes where it seals against the heat break, and molten plastic escapes around the threads instead of through the tip.
Does the nozzle diameter have to match anything?
Only the slicer profile. The orifice diameter — 0.4 mm on most printers — can be changed freely, as long as the slicer is told, because it sets the line width the software plans for.
Last reviewed 15 September 2026