Wood Cutting Calculator — Free Lumber Cut Calculator

What This Wood Cutting Calculator Does

Cutting lumber is a one-dimensional problem. A stud, a joist or a batten has a fixed cross-section, so the only question is length: which pieces share a board, and which board length leaves the least behind. The calculator above plans one cross-section at a time. For a whole job — studs, plates and rafters together — open the full app, choose 1D → Wood cutting, and every piece carries its cross-section; the optimizer groups the job by cross-section and plans each group on matching stock in a single run.

A Measured Example: A Garden Shed Frame

A small shed frame needs 34 pieces in two cross-sections, cut with a 3 mm blade. The yard sells 45 × 95 mm in 3.0, 3.6 and 4.8 m and 45 × 145 mm in 3.0 and 4.8 m. Both results below come from the optimizer itself (measured 25 September 2026), not from an estimate.

The honest reading: the board count is the same, and most of the saving comes from buying the right length, not from clever ordering. A 2400 mm stud on a 3.0 m board leaves 597 mm — exactly enough for a 560 mm noggin — while the same stud on a 4.8 m board leaves 2.4 m that the rest of the list cannot fill well. Comparing every length your yard sells, for every cross-section, is the arithmetic the calculator does for you.

How to Use This Lumber Cut Calculator

1. Enter the boards you can buy

   Add every stock length the yard sells for the cross-section — 3.0, 3.6, 4.8 m, or 8, 10, 12, 16 ft. Add a price per board if you want the plan ranked by cost instead of by lumber used.

2. List every piece

   Enter the length and quantity of each piece. In the app’s Wood cutting mode, the Parts to cut table also takes the cross-section, so one list covers the whole job; you can paste it from Excel as Name, Qty, W, H, Length.

3. Set kerf and trims

   Set Blade kerf (mm) — about 3 mm for a circular or mitre saw. If board ends are split or checked, set a Start trim and End trim; that length is cut off every board and counted as waste.

4. Run and read the plan

   The plan lists how many boards of each length to buy, which pieces come from each board, and the offcut left on every board. Offcuts shorter than Min. reusable size are treated as waste.

5. Export and cut

   Print the plan, or export a PDF for the saw and a CSV for your order. With a free account you can save usable offcuts to the offcut inventory and use them first on the next job.

Standard Lumber Sizes

Stocked lengths vary by yard and region — enter what your supplier actually sells, and measure boards that must be exact.

Who Uses a Wood Cutting Calculator?

Carpenters and framers

Studs, plates, noggins and rafters come in a handful of cross-sections and a long list of lengths. Planning them in one run tells you what to order before the delivery is booked, instead of discovering on site that the last plates need another board.

Deck, fence and pergola builders

Joists, bearers, posts and deck boards are bought by the length, and the lengths you order decide how much ends up as offcuts. Comparing the stocked lengths is usually where the saving is — the measured example above shows why.

Furniture makers working in solid wood

Rails, legs and battens for tables, beds and frames are cut from boards of fixed cross-section. The optimizer places short pieces in the offcuts of long ones, and the offcut inventory keeps the useful leftovers for the next job. For sheet goods such as plywood and MDF, use the board cutting calculator instead.

DIY builders

A workbench, a raised bed or a shed: enter the pieces, run it, and take the list to the yard. You know exactly which boards and how many to buy.

Tips for Better Lumber Cutting

• Keep one cross-section per stock row. 45 × 95 and 45 × 145 are different stock even if they come from the same yard; the app’s Wood cutting mode keeps them apart automatically.
• Account for blade kerf. Every cut removes a few millimetres; 20 cuts with a 3 mm blade remove 60 mm. Leaving kerf out means the last piece on a board comes up short.
• Reuse your offcuts. A 1.2 m offcut from the last job is still a board. Save it to the Offcut inventory: with Use off-cuts automatically on, the optimizer cuts from it before a new board of the same cross-section. A length you type in as a stock row is an ordinary stock length — with Unlimited supply, one you can buy again.
• Use prices when lengths cost differently per metre. Long boards often cost more per metre; with prices entered, cost mode ranks plans by total price instead of lumber used.

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