What does the u mean in Gridfinity bin heights?

One u is 7 mm. A 3u bin is about 25 mm tall inside. The step size keeps stacked bins level with each other.

Why is the Gridfinity grid 42 mm?

Zack Freedman chose 42 because it splits cleanly into many smaller sizes, and as a nod to a famous science fiction book. The number is permanent, so parts never stop fitting.

What size magnets does Gridfinity use?

Discs 6 mm across and 2 mm thick, up to four per cell in bins with magnet holes. Drawer setups usually skip them.

2026-08-03 · 5 min read

Gridfinity dimensions and sizes: the 42 mm cheat sheet

A gray 4 by 4 Gridfinity baseplate photographed on a plain white background, showing the raised grid walls

Gridfinity sizes are simple once you know two numbers. The grid is 42 mm per square. Bin heights go up in 7 mm steps. Every part in the system is built from those two numbers. That is why any bin fits any baseplate, from any maker, forever.

Zack Freedman designed it this way on purpose. He promised the standard will never change. So a bin you buy today will still snap into a plate you buy in five years.

The core spec table

Spec	Number	Notes
Grid cell	42 x 42 mm	About 1.65 inches square
Height unit (u)	7 mm	Bin heights are counted in u
Base height	About 5 mm	The socket the baseplate grips
Magnet size	6 x 2 mm disc	Up to 4 per cell, optional
Baseplate tiles	Any grid, like 4x4 or 6x6	Tiles sit side by side for big drawers

The footprint: how wide and deep

A bin's footprint is counted in grid squares. A 1x1 bin covers one square. A 2x2 bin covers four. Nothing ever pokes past the edge of its squares. That rule is what makes every layout work.

Footprint	Real size	Best for
1x1	42 x 42 mm	Screws, nuts, coins, SD cards, small parts
2x1	84 x 42 mm	Pens, bits, short tools, cables
2x1 split	84 x 42 mm, 2 slots	Two small parts that belong together
2x2	84 x 84 mm	Tape, chargers, pliers, bulky items
2x3	84 x 126 mm	Long tools, boxes, big gear

The height: how tall

Heights are measured in units of 7 mm, written as u. A 3u bin is about 25 mm tall on the inside wall. Matching heights look clean in a drawer. Mixed heights are fine too, and shorter bins can stack.

Height	About	Fits a drawer with clear height of
2u	18 mm	25 mm and up
3u	25 mm	32 mm and up
4u	32 mm	39 mm and up
6u	46 mm	53 mm and up

Quick rule: measure your drawer's clear height, subtract about 7 mm for the baseplate and some finger room, and pick the tallest bin that fits. Most people are happiest with 3u in kitchen and desk drawers and 4u or 6u in shop drawers.

A purple printed Gridfinity crate held in an open palm, showing the milk-crate lattice walls and stacking rim

Baseplates: the part people forget

Baseplates are the grid itself. Each socket has a shaped edge with a small lip. Bins drop in with no force, but the lip stops them from sliding when you open and close the drawer.

Baseplates come in tiles, like 6x6, 6x5, or 4x4. Big drawers use several tiles side by side. Your drawer will almost never divide evenly into 42 mm squares, so a well-planned kit widens the border of the outer plates to fill the gap. Our drawer planner does that automatically.

What about Gridfinity 2.0?

Gridfinity 2.0 is Zack Freedman's update to his own spec. The grid stayed 42 mm, so nothing stopped fitting. The biggest practical change: magnets became optional instead of expected. Every number in this sheet still holds.

What fits in what: cheat sheet

Screws and fasteners: 1x1 at 3u, one size per bin, add labels
Pens and markers: 2x1 at 3u or 4u
Screwdriver bits: 1x1 split or 2x1 split at 2u
Batteries: 1x1 at 2u for AA and AAA
Measuring tape: 2x2 at 4u
Pliers and cutters: 2x2 or 2x3 at 4u
Rolls of tape: 2x2 at 6u
Charging cables: 2x2 at 4u, one cable per bin ends the tangle

FAQ

What does the u mean in bin heights?
One u is 7 mm. A 2u bin is 14 mm of wall plus the base, about 18 mm total. The step size keeps stacked bins level with each other.

Why 42 mm and not 40 or 50?
Zack Freedman chose 42 because it splits cleanly into many smaller sizes, and because it is a nod to a famous book. The exact number matters less than the promise: it will never change.

Is a bigger bin always better?
No. The system works best when each bin holds one kind of thing. Lots of small bins beat a few big ones for parts. Save big bins for bulky items.

Do all brands of Gridfinity parts fit together?
Yes, if they follow the spec. Gridfinity is open under the MIT license, and the sizes are public. Our parts follow the spec and are printed in the USA.

Put the numbers to work: the Gridfinity generator plans a whole drawer from your measurements, and the Gridfinity hub has every part we print.

Watch more

Want something printed?

Browse the shop or upload your own file for a price in seconds.