Gridfinity explained: the 42 mm grid, bins, baseplates and magnets
Gridfinity is a free, open storage system built on a 42 mm grid: a baseplate holds the grid, and any bin sized in whole grid units clicks into it. It was created by maker Zack Freedman, and because the sizes are a public standard, bins from anyone fit baseplates from anyone.
The three numbers that matter
| Part | Size | What it means |
|---|---|---|
| Grid unit | 42 mm | One square of the baseplate. A 2 × 3 bin covers 84 × 126 mm. |
| Bin clearance | 0.5 mm | Bins are 0.5 mm smaller than the grid, so 1 unit is 41.5 mm across and drops in easily. |
| Height unit | 7 mm | Heights count in 7 mm steps: 3 units = 21 mm, 6 units = 42 mm. |
Under each grid square a bin has a stepped foot about 4.75 mm tall. The baseplate has the matching sockets, which is what stops bins sliding about.
Bins, lips and magnets
- Stacking lip. A rim about 4.4 mm tall on top of the bin. Another bin's feet sit in it, so bins stack without falling off. Leave it off for bins that live in a drawer with little headroom.
- Magnet holes. Small round magnets (6 × 2 mm) pressed into the feet and the baseplate hold bins in place when a drawer slams or a toolbox tips. Without magnets, the feet alone are enough for most drawers.
- Baseplate. Print one to fill a drawer or a shelf, or several smaller ones side by side if your printer bed is small.
When Gridfinity is worth it — and when it isn't
Gridfinity shines when you rearrange often: tools, electronics parts, craft supplies. Every bin fits every spot.
It costs space and filament. The feet and baseplate take roughly 5–7 mm of height, and the 42 mm steps rarely match a drawer exactly, so up to 41 mm of a drawer's width or depth can be left over. For a drawer you set up once, a custom-sized set (see How to measure a drawer) usually holds more.
Making Gridfinity bins in SO3D
In the generator, choose File › Gridfinity… with a Box, Rectangular or Square base:
- Pick 1–7 units wide and deep (42–294 mm) and 2–20 units tall (14–140 mm).
- Tick Stacking lip if you want to stack.
- Everything else in SO3D still works on top: dividers, label slots, scoops, finger notches and shaped pockets cut to fit a tool.
- Magnet holes and a matching baseplate come with the Hobbyist plan.
Worked example: Gridfinity in the same drawer
Take the 380 × 460 mm drawer from How to measure a drawer. It holds a grid of 9 × 10 units (378 × 420 mm), leaving 2 mm spare across and 40 mm at the back, which is a handy slot for a ruler or a pen.
A 70 mm drawer leaves room for bins up to 8 units tall (56 mm) once the baseplate sits underneath. On a 180 mm printer, print the baseplate as several pieces of up to 4 units (168 mm) across and lay them side by side.
Common questions
Do SO3D bins fit other Gridfinity baseplates? Yes. They follow the standard 42 mm grid, 0.5 mm clearance and 7 mm height steps, so they click into any standard baseplate.
Do I need magnets? No. The feet keep bins in place in a drawer. Magnets help in toolboxes, on slopes and in drawers that slam.
Can I use Gridfinity on the free plan? Yes: Gridfinity bins, the stacking lip and every other feature work on Starter. Magnet holes and the matching baseplate are part of Hobbyist.
Gridfinity or a custom set? Gridfinity if you rearrange often or share bins between drawers; a custom set (How to measure a drawer) if you set the drawer up once and want to use every millimetre.
Try it yourself — free, in your browser.
Open the generator