How to Build a Garage Wall Cabinet (Free Plans + Cut List)

The cabinet we're building

• Outer size: 30" wide × 30" tall × 12" deep
• Material: One sheet of 3/4" plywood (birch or sanded pine)
• Back: 1/4" plywood, nailed and glued into a rabbet
• Shelves: One fixed center shelf in dadoes
• Mounting: French cleat, so you can move it later

Step 1 — Measure your plywood before you cut anything

This is the step everyone skips. A sheet sold as 3/4" plywood usually measures about 0.703" (roughly 23/32"). If you design the cabinet on paper assuming a true 0.750", every shelf you cut will be about 1/16" too long and your case won't close up square.

Put a caliper on the sheet in three spots and write the number down. If you don't own a caliper, stack two offcuts and measure with a tape, then halve it. Full explanation in the nominal vs actual plywood thickness guide.

Step 2 — The cut list

Using a measured thickness of 0.703" and a 30 × 30 × 12 carcass:

Part            Qty   Size (T × W × L)
Sides            2    0.703" × 12"    × 30"
Top / Bottom     2    0.703" × 12"    × 28.594"
Fixed shelf      1    0.703" × 11.25" × 28.594"
Back             1    0.25"  × 29"    × 29"
Cleat (wall)     1    0.75"  × 4"     × 28.5"  (45° bevel)
Cleat (cabinet)  1    0.75"  × 4"     × 28.5"  (45° bevel)
Doors (opt.)     2    0.703" × 14.75" × 29.5"

The horizontal parts are 28.594", not 28.5". That comes from:

30" outer width − (2 × 0.703" side thickness) = 28.594"

If your sheet measures something else, the number changes. Plug your real thickness into the cut list calculator and it recalculates every part instantly — pick the "Modular Garage Wall Cabinet" template.

Step 3 — Break down the sheet

Rip the 12"-deep parts first: two rips off the long edge of the sheet gives you all four carcass pieces plus the shelf. Cut to a fence, never to a pencil mark, so the blade kerf lands in the offcut instead of your part. Three rips at a 1/8" kerf removes 3/8" of sheet — plan the layout with that in mind. More on this in the saw kerf guide.

Step 4 — Joinery that holds tools, not decorations

• Dadoes for the shelf: 3/8" deep, cut to your measured plywood thickness. A dado stack set to 0.703" beats a "3/4-inch" dado every time.
• Rabbet for the back: 1/4" wide × 3/8" deep on all four rear edges. A captured back is what keeps the box square under load.
• Pocket screws or dominoes at the top/bottom: glue plus mechanical fastening. Garage cabinets hold paint cans and power tools, so don't rely on glue alone into plywood end grain.

Step 5 — Mount it with a French cleat

Rip a 4"-wide strip of 3/4" plywood at 45°, giving you two mating cleats. Screw one to the wall into studs (level it — everything else follows this line), glue and screw the other inside the cabinet at the top. Lift the cabinet on. It hangs, holds hundreds of pounds, and lifts off when you rearrange the shop.

Step 6 — Doors (optional)

For a 30" opening with a 28.594" interior, two overlay doors at 14.75" wide leave a clean 1/8" reveal down the center. Cut them from the same sheet, apply edge banding, and use concealed euro hinges with a 35mm cup bore. If you'd rather skip doors, add a second shelf and treat it as open storage — faster, cheaper, and easier to grab from.

Common mistakes

• Designing at 0.75" thickness instead of your measured thickness.
• Cutting shelves to the outer width instead of the interior width.
• Skipping the back panel, then wondering why the case racks out of square.
• Mounting into drywall instead of studs. Use the cleat, hit the studs.
• Forgetting that 1/4" back plywood is usually closer to 0.205".

Get your exact numbers

Every dimension above assumes a 30 × 30 × 12 cabinet and 0.703" plywood. Your wall, your sheet, and your blade are different. Open the WoodCraft Utility Engine, choose the garage wall cabinet template, enter your measured thickness and kerf, and it prints a cut list that fits the first time. See more builds on the garage storage cabinets page.