Guide, 2026-11-04

How to plan modular 3D-printed drawer organiser trays on a grid

Open drawer organisers work best when they fill the drawer with no wasted gaps and no sliding around. The simplest way to get there is a grid: every tray is a whole number of units wide and deep, so any mix of sizes fits together. This guide shows how to measure, plan the layout and print a first tray, using a 42 mm unit as the example.

Step 1: measure the inside of the drawer

Take three measurements in millimetres, using the inside of the drawer, not the front panel:

• Width, left to right.
• Depth, front to back.
• Height, from the floor to the underside of whatever sits above when the drawer is closed, or to the top of the drawer box.

Measure at the bottom, where the trays will sit. Drawers are often slightly narrower there than at the rim, and corners can be rounded or have rails.

Step 2: count the grid units

Divide width and depth by the unit size and round down. With a 42 mm unit, a drawer measuring 350 x 450 mm gives:

• 350 / 42 = 8.33, so 8 units across.
• 450 / 42 = 10.71, so 10 units deep.
• 8 x 10 = 80 units of floor space.

The leftover is 350 - 8 x 42 = 14 mm across and 450 - 10 x 42 = 30 mm deep. Leave it empty, or use it for something thin and flat such as a ruler or a pad.

Step 3: allow for a gap

If every tray were exactly n x 42 mm, any printing variation would make neighbours jam. A common approach is to make each tray slightly smaller than its grid cell. In the TrayKit set, for example, a tray n units long is n x 42 - 0.5 mm, so a 1-unit tray is 41.5 mm, a 2-unit tray 83.5 mm, a 3-unit tray 125.5 mm and a 4-unit tray 167.5 mm. The 0.5 mm gap between neighbours gives a little play.

Step 4: choose sizes and a height

Sort what you store into groups and give each a tray. Small things such as pins, batteries and screws suit 1x1 or 1x2 trays. Cables and cutlery suit long, narrow ones. Tools and gadgets need larger squares. Keep the tallest item in mind: a tray must be lower than the drawer height, with room to lift things out. Use a shallow tray for flat objects and a taller one for anything that would tip.

A worked layout

For the 8 x 10 grid above, one way to fill it with 2 x 4 unit trays is to turn them so the long side runs across the drawer. Two trays side by side fill the 8-unit width. Each row is 2 units deep, so 10 / 2 = 5 rows fit, giving 10 trays and 10 x 8 = 80 units, which uses the whole grid. In practice you would mix sizes, for example:

The units add up: 32 + 18 + 18 + 12 = 80. Draw the grid on paper first, shade each tray and check that no row is longer than 8 units or deeper than 10.

Step 5: check your printer and print one tray

Look at the footprint of the largest tray. A 2 x 4 tray is 167.5 x 83.5 mm and a 3 x 3 tray is 125.5 x 125.5 mm, so your bed must be big enough, and the build height must cover the tray height. Then print settings. These are starting suggestions, not tested profiles:

• PLA or PETG.
• 0.2 mm layer height.
• 2 to 3 walls.
• No supports, if the tray has a flat bottom and no steep overhangs.

Printers differ in how accurately they hold size. Print one 1x1 tray before anything else and test it in the drawer. If it is too tight or too loose, adjust your slicer's size compensation or flow setting and try again, then print the rest.

Common mistakes

• Measuring the drawer front instead of the inside.
• Rounding up when counting units, so the last row does not fit.
• Printing the whole set before checking one tray.
• Choosing a tray taller than the drawer allows.
• Forgetting that rails or rounded corners reduce usable space.

When ready-made files save time

You can model your own trays, but a consistent set saves effort. TrayKit is 16 STL files for FDM printers: 8 footprints from 1x1 to 3x3 units, each in 25 mm and 45 mm heights, with 1.6 mm walls, a flat bottom and a layout guide with a printable reference sheet. The files were checked by software for watertight meshes and dimensions, but they have not been test-printed by us, and the print settings in its README are suggestions. There is no custom size generator, lid, divider or baseplate, and the files are for your own use only.