Build this DIY bookshelf as a 36-inch-wide, 72-inch-high, 12-inch-deep case with a center divider. The divider reduces each shelf span to about 16 7/8 inches, which is far more suitable for dense rows of books than a decorative, unsupported 36-inch shelf.
This bookshelf DIY project uses 3/4-inch plywood, two fixed shelves, six adjustable shelves, a full plywood back, and a 3-inch plinth. The finished case is 72 inches high; the plinth raises the overall height to approximately 75 inches.
DIY Bookshelf Dimensions: Size a 36 × 72 × 12-Inch Case
Start with a quick book inventory. Measure your tallest hardcovers, paperbacks, and oversized volumes. Set most clear openings at 10 to 12 inches, with one 13- to 14-inch opening for tall books. A 10 1/2- to 11-inch shelf depth accommodates typical books while keeping the case compact.
- Overall case: 36 inches wide, 72 inches high, and 12 inches deep, including the back.
- Carcass depth: 11 3/4 inches, with a 1/4-inch back applied to the rear.
- Shelf depth: 11 1/4 inches, leaving clearance behind the books.
- Internal shelf span: approximately 16 7/8 inches per bay after adding the center divider.
- Material thickness: 3/4-inch plywood for sides, shelves, top, bottom, and divider.
Use the 3/4-inch shelves for dense book loads. Fixed shelves should support the case and divide tall openings; adjustable shelves provide flexibility for changing book sizes. Do not treat a long, thin decorative shelf as adequate for heavy books.
Check the wall before cutting. Measure the baseboard height and projection. Use a 3-inch toe or plinth, and notch its rear corners to clear the baseboard. If necessary, notch the lower rear corners of the case as well. Keep the case’s front edge aligned with the room, not forced tightly against the trim.
Bookshelf Plans: Materials, Cut List, Fixed and Adjustable Shelves
Use two sheets of 3/4-inch plywood and one 1/4-inch plywood panel. Also gather wood glue, 1 1/4-inch screws, shelf pins, sandpaper, edge banding or hardwood strips, finish, shims, and two wall-anchoring brackets.
Cut these parts:
- Two sides: 72 × 11 3/4 inches.
- Top and bottom: two pieces at 34 1/2 × 11 3/4 inches.
- Center divider: 70 1/2 × 11 3/4 inches.
- Eight shelves: 16 5/8 × 11 1/4 inches. Use two as fixed shelves and six as adjustable shelves.
- Back panel: 36 × 72 inches from 1/4-inch plywood.
- Plinth: two 36 × 3-inch strips and two 9 × 3-inch strips, assembled into a 36 × 10 1/2-inch footprint.
Cut 1/4-inch-deep dados for the center divider and fixed shelves if you have a router or dado blade. Otherwise, use glue and screws through the sides, with screws through the divider into the top, bottom, and fixed shelves. Drill adjustable shelf-pin holes in straight, parallel rows before assembly.
Ease exposed plywood edges with edge banding or hardwood strips. This protects the front edges from chipping and gives the shelves a stronger finished lip.
Assemble and Square the Case: Joinery, Back, and Anti-Racking
- Cut every part, label it, and dry-fit the case without glue. Confirm that the shelves slide into both bays and that the divider fits between the top and bottom.
- Sand interior faces with 120-grit paper before assembly. It is easier to reach them now.
- Glue and fasten the top and bottom between the sides. Add the center divider and fixed shelves, checking that each joint closes fully.
- Measure both diagonals from opposite corners. Shift the case until the measurements match, or differ by no more than 1/8 inch.
- Apply the back panel while the case is square. Glue its perimeter and fasten it with screws or nails every 6 to 8 inches. The back is essential for anti-racking; it should not be a loose dust cover.
- Assemble the plinth separately, position it beneath the case, and fasten the case to it through the bottom.
Recheck the diagonals after securing the back. Install shelf pins only after the case is stable, then test every adjustable shelf for a level bearing surface.
Finish, Place, and Load: Cure, Level, Anchor, and Add Books Gradually
Sand visible surfaces with 180-grit paper, remove dust, and apply paint, polyurethane, or another compatible finish. Coat shelf edges carefully. Allow the finish to cure according to its label; do not load books while it remains soft or tacky.
Set the plinth in position and place the case on top. Check level from side to side and front to back. Insert firm shims beneath the plinth rather than bending the case to compensate for an uneven floor. Secure the upper case to wall studs with brackets through the back or side framing. Wall restraint prevents tipping, especially when upper shelves are full.
Load the bottom shelf first, then add books to each level progressively. Keep the heaviest books low, stand volumes upright, and watch for shelf deflection or movement after each loaded bay. Stop and correct any wobble before adding more weight.