Gridfinity Magnet Size
The community gridfinity magnet size is a 6 × 2 mm disc, seated in a Ø6.5 × 2.4 mm pocket in the bin's foot: half a millimeter of diametral play and 0.4 mm of depth reserve hold a friction fit or a drop of glue. The gridfinity magnet size tool above turns any magnet you actually own into the right pocket numbers — and prints a test block, so the first bin you make is not the first one you scrap.
Holes are where 3D printing humbles every plan: extruded circles come out smaller than modeled, and a pocket that measures perfect on paper can pinch a real magnet. That is why the gridfinity magnet size workflow here ends in a physical fit test rather than a promise — five pockets at increasing clearance, printed and tried before you commit a whole drawer fleet.
The standard gridfinity magnet size
Six by two millimeters is the gridfinity magnet size the community settled on, which is why standard bins carry Ø6.5 × 2.4 mm pockets in their feet. The numbers come from the general rule the system applies everywhere: hole diameter equals magnet diameter plus 0.5 mm, and hole depth equals magnet thickness plus 0.4 mm. Run that rule against the 6 × 2 mm disc and the standard pockets fall out as Ø6.5 × 2.4 mm — every gridfinity magnet size question eventually lands on those two additions.
How the gridfinity magnet size rule works
| Quantity | Rule | Standard 6 × 2 mm result |
|---|---|---|
| Hole diameter | magnet diameter + 0.5 mm | Ø6.5 mm |
| Hole depth | magnet thickness + 0.4 mm | 2.4 mm |
| Diameter range accepted | 3 mm to 15 mm | — |
| Thickness range accepted | 0.5 mm to 6 mm | — |
The extra 0.5 mm and 0.4 mm are not sloppiness; they are the clearance that lets a printed hole accept a real magnet despite wall wobble and first-layer squash. Custom discs feed the same formulas, so anything you can buy a bag of gets pockets that follow the gridfinity magnet size logic exactly. Two additions really are the whole gridfinity magnet size decision — the rest is your printer's opinion of them.
The five-pocket gridfinity magnet size fit-test block
The block generated above carries five pockets for your magnet, cut at +0.3 through +0.7 mm of diametral clearance and labeled with raised dots so you can identify a winner by touch after the calipers go away. Drop the magnet into each pocket in turn and note where it slides home and holds without force. It is the fastest way to settle the gridfinity magnet size question on your own machine.
- +0.3 mm — one raised dot, the tightest pocket.
- +0.4 mm — two raised dots.
- +0.5 mm — three dots, the recommended gridfinity magnet size clearance.
- +0.6 mm — four raised dots.
- +0.7 mm — five dots, the loosest pocket.
How to use the gridfinity magnet size tester
- 1
Enter your magnet
Type the diameter and thickness from the box; the recommended hole updates using the +0.5/+0.4 rule.
- 2
Print the test block
Download the gridfinity magnet size fit-test STL with its five dot-labeled pockets and print it in your normal material.
- 3
Try each pocket
Press the magnet into every pocket from one dot to five; the right gridfinity magnet size clearance grips without force.
- 4
Generate the bins
Take the winning clearance to the bin generator's magnet pockets and print the fleet with your verified gridfinity magnet size settings.
Print tolerance: why holes lie
FDM holes shrink for well-known reasons: circles become polygons at the layer level, and the perimeter laid into a curve pulls slightly inward. Resin printers carry their own exposure-driven drift. Whichever machine you run, the cure is identical — stop trusting modeled diameters and start measuring printed ones, which is precisely the habit the gridfinity magnet size test block builds into your workflow. The block exists because tolerance belongs to the machine, not the model — every gridfinity magnet size verdict is printer-specific.
Reading the fit like a machinist
Where the gridfinity magnet size fits in the wider system
Magnets are an upgrade, not a requirement: bins lock into their sockets by geometry alone, and a plain drawer full of bins behaves perfectly without a single disc. The gridfinity magnet size question earns urgency only when plates ride on steel surfaces, magnetic strips or drawers that slam shut — at that point, pockets sized by the rule above keep every bin exactly where you left it, through the whole system of plates, bins and accessories.
Never scale a pocket to fix a fit — scaling distorts the whole part. Reprint at the next clearance step instead, and let the raised dots referee your gridfinity magnet size tests.
Sources & references
“Gridfinity storage is built on a 42 mm square grid with 7 mm height units” — the community-maintained open specification this site implements and cross-checks against.
- Gridfinity community specification— the community-maintained geometry specification our models implement
- Gridfinity reference documentation— profile reference used to verify the foot, lip and socket dimensions
- Gridfinity Rebuilt (OpenSCAD)— open-source reference implementation we cross-check generated geometry against
Frequently Asked Questions
What size magnets does gridfinity use?
The common gridfinity magnet size is a 6 × 2 mm disc seated in Ø6.5 × 2.4 mm pockets. The tool also accepts custom discs from 3 mm to 15 mm across and 0.5 mm to 6 mm thick.
How deep should gridfinity magnet holes be?
Magnet thickness plus 0.4 mm — 2.4 mm deep for the standard 2 mm disc. The gridfinity magnet size rule covers depth and diameter alike, so both come from the same two additions.
What do the raised dots on the block mean?
One to five dots rank the pockets from tightest (+0.3 mm) to loosest (+0.7 mm). Find the dot whose pocket holds your magnet snugly, and you have found your personal gridfinity magnet size clearance.
Can I skip the fit-test block?
You can — the recommended gridfinity magnet size hole of +0.5 mm diameter suits most printers — but one test print is cheaper than reprinting a fleet of bins whose pockets pinch.