How this calculator works
This is a strip-packing method, which is how most panel saws and track saws are used. The parts are grouped by width. Each group is cut into strips of that width from the length of the sheet, with part lengths packed into each strip, longest first. The strips are then stacked across the width of the sheet, again widest first, and every group of strips that fills a sheet is one sheet to buy.
Worked example: the default list is a 600 mm base unit: two sides, a bottom, two stretchers, a shelf and two doors. It needs 8 parts totalling 2.0 m², packed into 4 strips on 2 sheet (33% used). Allowing the parts to turn makes no difference here.
A cutting-plan program using more complicated cuts can sometimes save a sheet, but such layouts are harder to cut. If your result is only just over a sheet, check the list for a part that could be a little smaller or cut from a leftover piece.
Assumptions and sources
The assumptions behind your numbers (waste, sizes, rates) are listed in the notes directly under your results, and they update when you change an input.
The formula and a worked example are shown above, so you can check any result by hand. Read how we calculate and check our numbers. Results are estimates for planning: supplier products vary, so check the size printed on the label.
Tips before you buy
- Length is along the grain, or the long side of the sheet. If the grain does not matter (painted MDF, for example), tick the box so parts can be turned and sheets are saved.
- Rip the sheet into strips first, then cut each strip to length: it is how a panel saw works and gives cleaner, safer cuts than wrestling a whole sheet.
- Add the width of the saw cut when you measure for the next part. This calculator already allows for it between parts.
- Add 5 to 10% for mistakes and defects, particularly on veneered boards where the face must be chip-free.
- Keep the leftover pieces: they make shelves, plinths and strips for the next job.
Tools & materials for this project
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Frequently asked questions
How do I work out how many sheets of plywood I need?
List every part with its size and quantity and pack them onto the sheet. Dividing the total area of the parts by the sheet area gives a lower limit; the real answer is higher, because of the saw cuts and parts that do not fit together. This calculator does the packing.
What is a cut list?
A table of every part you need to cut, with its length, width and quantity. It stops you wasting sheets and finding out mid-build that you are short.
Is it cheaper to buy half sheets?
Sometimes. Many stores sell half sheets (1220 × 1220 mm or 2440 × 610 mm) at a slightly higher price per area, but they are easier to carry and fit in a car. Choose the sheet size in the calculator to compare.
Should I allow for the saw cut?
Yes. Each cut removes about 3 mm, and over a sheet that adds up to a strip. The calculator allows for it.
Does grain direction matter?
On veneered boards and for visible faces it does: the grain should run the same way on doors and sides. On painted MDF or hidden parts it does not, so tick the box to let parts turn.
Add this calculator to your website
Running a blog, a contractor site or a class page? You can put this calculator on it for free. Copy the code below, and please leave the link underneath the calculator in place. The small script just resizes the frame to fit the results; if your site strips scripts, the calculator still works inside a scrolling frame.
Related calculators & guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.