Free bookcase plywood cut calculator

What this calculator does

A bookcase is a small set of parts that has to fit together cleanly: two sides, a top and a bottom, a stack of shelves, and a back. This calculator takes those parts and works out how to lay them on full plywood sheets with as little waste as possible. Instead of sketching it on the sheet and hoping, you get a numbered cutting plan, a clear cut list, and the exact number of 4x8 ft sheets to buy. cutlistlab does all of this in your browser, so there is nothing to install and no account needed.

To get your part sizes, start from the outside dimensions. The sides run the full height. The top, bottom and each shelf span the inside width, which is the bookcase width minus two side thicknesses. The back runs the full height and width in thinner plywood and ties the case square.

How to use it

1. Sketch the bookcase. Decide the overall height, width and depth, and how many shelves you want. Note where each shelf sits.
2. Derive the parts. Enter two sides at full height, a top and bottom and each shelf at the inside width, and a back panel. Give every part a clear name (side, shelf, top) so the cut list is easy to read at the saw.
3. Pick your plywood sheet. Choose a standard 4x8 ft (1220x2440 mm) sheet or enter your own size. Add any offcuts you already have so they get used first.
4. Set the kerf and grain. Enter the width your blade removes per cut, then mark the sides (and any visible part) as grain-fixed so the grain runs vertically.
5. Read the plan. The calculator packs everything onto the fewest sheets, draws the layout, lists the cuts in order, and tells you how many sheets you need and what is left over for the next project.

Shelf spans and plywood grain

Two things make or break a plywood bookcase: how far a shelf spans, and which way the grain runs. Plywood is strong, but books are heavy and a long shelf will bow over time. As a practical rule, keep the clear span (the open distance between supports) under about 30 in for books on 3/4 in plywood. If your bookcase is wider than that, add a center divider so each bay stays short, or glue a hardwood lip along the front edge to stiffen the shelf. Edge banding the front edges also hides the plies and gives a finished look.

Grain direction matters for looks and strength. On the sides, run the face grain vertically so it reads cleanly and the long edges stay stiff. Mark every visible part as grain-fixed and the optimizer respects it while still packing tightly. The back, which nobody sees, can rotate to fill gaps. Kerf and any trimmed edge are built into the plan, so the sheet count is realistic rather than theoretical.

A worked example

Here is a typical tall plywood bookcase so you can see the cut list before cutting. As an example, a 900 mm wide, 2100 mm tall bookcase in 18 mm plywood needs two side panels, a top and a bottom, three fixed shelves and a back panel. The cabinet designer (kast-helper) builds this part list automatically from a few measurements: width, depth, height and the number of shelves. You set grain direction so the plywood face veneer runs the right way, and the kerf so the saw width is accounted for.

With these parts the optimizer packs onto about two sheets of 18 mm plywood, roughly 20% offcut in this example, and gives you a numbered cutting order to follow at the saw. You can switch the goal between least waste, fewest cuts and lowest cost, drag a part by hand, and send any usable leftover to your offcut stock for the next project. Edge banding allowance, labels, CSV export and mm or inch units are all included.

Frequently asked questions