Bookshelf cut list: every part from one sheet of plywood

What this cut list assumes

The bookshelf this page works out is the plainest one there is: two sides that run the full height, a top and a bottom that fit between them, and shelves the same length as the top. Everything is the same depth. There is no back, no face frame, no doors and no toe kick.

That is a statement about the arithmetic, not a recommendation. The page does not say how to join the parts, how far a shelf can span without sagging or what screws to use — those depend on the plywood, the load and the tools you have, and a number here would be a guess dressed up as a measurement. What it does do is turn three outside measurements into the exact list of rectangles to cut, and then lay those rectangles out on a sheet the way a saw can cut them.

How the parts are counted

Start from the outside of the finished bookshelf. Using the default above —32 in wide, 72 in tall, 11 1/4 in deep, in 3/4 in plywood, with four shelves — the list is:

• Two sides, 11 1/4 in × 72 in. A side is as tall as the bookshelf and as deep as it.
• A top and a bottom, 11 1/4 in × 30 1/2 in. They sit between the sides, so they are shorter than the bookshelf is wide.
• Four shelves, the same 11 1/4 in × 30 1/2 in. The number you type is the shelves between the top and the bottom; the top and the bottom are not counted in it.

That is 8 pieces, and six of them are the same size.

Where the thickness is subtracted

Only one measurement on this list loses anything to the plywood’s thickness: the length of the parts that fit between the sides. The width is measured across the outside of both sides, so what is left between them is

shelf length = outside width − 2 × thickness

32 − 2 × 3/4 = 30 1/2 in. It is two thicknesses, not one — one for each side — and forgetting the second gives a shelf 3/4 in too long to go in.

The height and the depth lose nothing. The sides run from the floor to the top of the bookshelf, so they are the full height; the top and the bottom sit inside that height rather than adding to it. Every part is the full depth, because there is no back for anything to stop short of.

Use the thickness the plywood actually is. Sheets sold as 3/4 in often measure 23/32 in, and on this bookshelf that changes the shelves from30 1/2 in to 30 9/16 in. Measure a sheet with calipers or a good rule, type the number you get, and the list follows it.

Tops between the sides, or over them

There are two ways to put a top on a box, and they give different cut lists. This page uses the first: the top and the bottom sitbetween the sides, and the sides are the full height. In the second, the top and the bottom lie over the ends of the sides, so they are the full width and the sides are shorter instead:

side length = outside height − 2 × thickness

For the default bookshelf that means sides of 70 1/2 inand a top and bottom of 32 in. The shelves do not change: they still fit between the sides, so they are still 30 1/2 in. Both versions come out of one sheet. If you build the second, change the three lengths on the PDF by hand, or enter the parts in the plywood cut calculator.

The words overlay and inset are also used about doors, for a door that covers the front of the box and one that sits inside it. That is a separate choice with its own arithmetic, and this bookshelf has no doors.

Why it fits one sheet

A 4 × 8 sheet is 48 in across. Four strips 11 1/4 in wide need four widths and the three kerfs between them, 45 3/8 in — so four strips fit, with the grain running along each. Two strips give the sides: a 72 in side leaves23 7/8 in of the strip after the cut, which is too short for a 30 1/2 in part. The other two strips are crosscut into three 30 1/2 in pieces each, which is exactly the top, the bottom and four shelves. The plan above does the same, in12 cuts, and wastes 20.2% of the sheet, counting the offcuts.

Reading the cut list for this bookshelf

Under the drawing are the 12 cuts in an order a saw can make them:4 rips along the sheet and 8 crosscuts across the strips they leave. The first is a rip 11 1/4 in from the factory edge, which leaves an 11 1/4 × 96 in strip and the 36 5/8 in wide remainder of the sheet. Every rip after it is measured from the fresh edge of that remainder, and the last one leaves a strip 2 1/2 in wide that nothing on this list needs.

Each line names both pieces a cut leaves, so you can check a tape against the paper before the next cut: if the remainder in front of you is not the width the list says, stop and find out why while the sheet is still whole. The PDF carries the same list, numbered, under a drawing of the sheet.

A metric sheet changes nothing here. 2440 × 1220 mm is a hair larger than 48 × 96 in, and the default bookshelf comes out of one of those too — pick it under Sheet and the cut list is worked out again.

Mistakes that cost a second sheet

That layout has almost no slack, which is why small changes matter. Each of these was worked out by the same code as the form:

• Making it 12 in deep. Four 12 in strips need 48 3/8 in, more than the sheet has, so only three fit and the plan takes2 sheets. At 11 7/8 in deep it is one sheet again.
• Adding a fifth shelf. The two shelf strips hold six pieces, and a top, a bottom and five shelves are seven. That is 2 sheets.
• Making it 36 in wide. Shelves of 34 1/2 inonly fit two to a 96 in strip, so with the grain kept it is2 sheets. Untick the grain box and it is1 sheet, because some shelves are turned across the sheet — which also turns their grain across them.
• Subtracting the thickness once. Shelves cut to 31 1/4 in instead of30 1/2 in are 3/4 in too long.
• Counting the top and the bottom as shelves. Four shelves means four between them; typing six gets eight pieces that size and a second sheet.
• Sizing to the nominal sheet. Parts sized to divide the sheet exactly lose a row to the kerfs. The form counts the kerf; a tape and a pencil often do not.

In millimetres

The same bookshelf in metric sizes: 800 × 1800 × 300 mm in 18 mm board, with three shelves, on a 2440 × 1220 mm sheet with a 3 mm kerf. The top, the bottom and the shelves are 800 − 2 × 18 = 764 mm, and the whole bookshelf comes out of one sheet. Switch the units in the form and every size you have typed is converted rather than reread.

Before the first cut

Check three numbers against the real material, not the label: the thickness of the plywood, the size of the sheet, and the width of your blade’s cut — cut a scrap and measure what went. Then read the parts table against your drawing. The list is exactly as right as the measurements typed into it.

Questions

How many sheets of plywood do I need for a bookshelf?

For a bookshelf 32 in wide, 72 in tall and 11 1/4 in deep in 3/4 in plywood, with a top, a bottom and four shelves: one 4 × 8 sheet, with the grain running along every part. Make it 12 in deep, add a fifth shelf or make it 36 in wide and it takes two. Put your own sizes into the form to see where your design lands.

How long should the shelves be?

In a bookshelf whose shelves sit between the sides, the outside width minus two thicknesses of the plywood. A 32 in wide bookshelf in 3/4 in plywood has 30 1/2 in shelves. If your plywood measures 23/32 in, they are 30 9/16 in.

Does the cut list include a back panel?

No. This template is an open bookshelf: two sides, a top, a bottom and shelves. A back is sized by how it is fitted, and the page does not guess that. For a back applied flat to the rear edges, add a part the full outside width and height to the plywood cut calculator.

Why does the plan keep the grain along every part?

On most plywood the face grain runs along the length of the sheet, and this template has it run along the length of every side and shelf. With the box ticked, no part is turned on the sheet. Untick it for a painted bookshelf and the calculator may turn parts if that saves material.

What is in the PDF?

The parts with their sizes, the totals, a drawing of each sheet with every part labelled, and the cuts in an order you can make them. It is made in your browser from what is on the screen; nothing is uploaded, and it prints in black and white.

Can I use millimetres?

Yes. Switch the units and everything typed is converted. A metric bookshelf of 800 × 1800 × 300 mm in 18 mm board with three shelves comes out of one 2440 × 1220 mm sheet, with 764 mm shelves.