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Tolerance Test Generator: Find Your Printer's Clearance

Choose a pin size and a range of gaps, and the generator builds a plate with a labelled hole for each gap and a pin in it. Print it, push each pin out or try to turn it, and the smallest gap that moves freely is the clearance to design your parts with.

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Demo with a sample file, recorded in this tool.

How to use a tolerance test

  1. 1

    Pick the gaps

    Set the smallest gap, the step and how many holes. 0.1 to 0.6 mm in 0.1 mm steps covers most FDM printers. The number next to each hole is the gap per side.

  2. 2

    Choose the style

    Print-in-place puts a pin inside every hole (tests clearance for hinges and moving parts). Separate pins print beside the plate (tests press and slide fits).

  3. 3

    Print it as usual

    Use the filament, nozzle and layer height you design for, no supports. Do not scale the STL, or the gaps change.

  4. 4

    Test each pin

    Push or twist each pin. Tight pins are a press fit, pins that slide are a loose fit. Use the smallest free gap in your own designs.

What the gap means

Gap is the space between the pin and the hole wall on one side. The hole is the pin diameter plus two gaps.

Gap per sideThe number printed next to each hole, in millimetres without the leading zero (.2 = 0.2 mm). A pin of 10 mm in a 0.2 mm gap sits in a 10.4 mm hole.
Stuck pinThe gap is too small for your printer: layer lines and elephant foot fused the pin to the plate. Do not use this gap for moving parts.
Tight pinMoves only with force: a press fit. Good for parts that should stay together without glue.
Free pinTurns or slides without force. The smallest free gap is your clearance for print-in-place hinges, lids and sliding parts.
Elephant footThe first layers spread out and can weld the bottom of a pin. If only the bottom sticks, turn on elephant foot compensation in your slicer and print again.

Printer tuned? Make a printable model with AI

Turn a photo or a sentence into a 3D model with an STL download, ready to slice. The AI generators use credits; this calibration tool does not.

Photo to STL with AI →Text to 3D model

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Tolerance test FAQ

It depends on the printer, filament and settings, which is why you print this test. Many FDM printers end up somewhere around 0.2 to 0.3 mm per side for parts that must move freely and less for press fits, but your own test result is the number to use.
Per side. The label .2 means 0.2 mm between the pin and the hole wall on each side, so the hole is 0.4 mm wider than the pin. The table under the preview lists every hole and pin diameter.
Print-in-place shows how much gap a part needs to come free after printing, as in hinges and captive joints. Separate pins show how parts that you print apart will fit together. If you design both, print both.
Usually elephant foot (a squashed first layer), over-extrusion or a seam on the hole wall. Turn on elephant foot compensation in the slicer, calibrate e-steps and flow, and check the first layer is not too low. Small gaps also depend on the hole being printed as a smooth circle.
Yes. Pin diameter, smallest gap, step, number of holes and plate thickness are all set in the generator, and the preview updates at once. The download is a ready STL in millimetres.
Yes. Use smaller gaps (for example 0.05 mm steps) and print it flat on the plate or with supports as your resin printer needs. Resin prints usually need smaller clearances than FDM.
No. The model is built in your browser and downloaded straight to your device. It is free, with no signup and no upload.

The STL holds the exact sizes in the table. Real gaps depend on your printer, slicer and filament; that is what the test measures.