I needed a small funnel when working on a project. Attached files are

• The Not Very Big Funnel (50mm). As you can see in the picture it's less than half the size of a normal household funnel. I printed this one in clear PETG with a .8 mm nozzle.
• The Smaller Funnel (40 mm) was the one I used for the project. Normal .4 mm nozzle and neon coloured PLA.
• I realized I could make it smaller. The Tiny Funnel has a diameter of just 32 mm. I printed it in PETG using a .25 mm nozzle.
• Yet smaller, 24mm, is Ze Smallestest Funnel.
• ...but with a lot of patience, I made an even smaller one (18mm), which fits inside the Ze Smallestest Funnel. It's the kind the Smurfs use to fill mushroom juice in their tiny flasks.

The funnel is available as a customizable OpenSCAD model. The attached drawing shows the parameters you can tweak. Enjoy!