Estimate how much lumber you need for framing or a custom cut list, lumber weight by species, and material cost — metric or imperial.
Method
Common spacings: 400mm or 600mm (metric); 16in or 24in (imperial), measured centre to centre.
The length of each vertical member — e.g. wall height for studs, or span for joists. Needed to work out stud material length, separate from the horizontal plate length below.
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Choose a quantity method: Framing Layout is for a run of studs or joists spaced on-centre (like a stud wall), while Custom Cut List is for a specific set of piece lengths and quantities, useful for shelving, fencing rails, or an irregular project. Enter your dimensions, pick the stock length your lumber is sold in, and add a waste allowance for offcuts. The calculator totals the length you need and rounds up to whole pieces. Use the Weight tab to estimate total lumber mass from a species density, and the Cost tab for a simple material cost estimate.
The amount of lumber you need depends on your project's total length and how that lumber is sold. For a framing run, that means the wall or floor length divided by your chosen on-centre spacing (commonly 400mm/16in or 600mm/24in) to get a member count, multiplied by each member's length (e.g. wall height), plus any plates. For a cut list — shelving, fencing, trim — it's simply the sum of every individual piece length multiplied by its quantity. Either way, the raw total gets a waste allowance added (5-15% depending on complexity) before being divided by your stock length and rounded up, since lumber is only sold in fixed lengths.
On-centre (OC) spacing is measured from the centreline of one framing member to the centreline of the next, not the gap between them. A simple stud count is calculated as the run length divided by the spacing, plus one for the starting member, then multiplied by the member length (e.g. wall height) to get the actual stud material needed:
If you're framing a wall, you can add top and bottom plates (or a double top plate, using 3 rows), which run the full length of the wall rather than being individual short members — these are added on top of the stud material, not instead of it. This calculator handles a straightforward run — it doesn't add corner studs, king/jack studs around window and door openings, or blocking, so add material for these separately.
For a project with several different piece lengths — like shelving at three different widths, or fence rails and pickets — add each length and how many you need. The calculator sums every entry into a single total length, then works out how many stock-length boards to buy the same way as the Framing Layout method. This total-length approach is simple and reliable, but it doesn't optimise how pieces are nested within each stock-length board (called cut-list optimisation), so a careful physical cut plan can sometimes use less material than the raw total suggests.
Lumber weight is volume multiplied by density. Volume comes from a board's thickness, width and length multiplied by how many pieces you have; density depends on the wood species and its moisture content. The formula is:
The species presets in the calculator are typical average kiln-dried densities from common reference figures — actual density varies by specific species, growing conditions and moisture content, sometimes by 15% or more. For structural design, transport weight limits, or other purposes where precision matters, use your supplier's measured or moisture-adjusted figure rather than a generic average.
The Cost tab multiplies either a price per piece or a price per linear foot/metre by the quantity calculated on the Quantity tab. This is a material-only estimate — it doesn't include labour, fasteners, hardware, delivery or waste disposal. Lumber prices vary significantly by species, grade, treatment and region, and change over time, so use your local supplier's current quoted price for an accurate total.
Example 1 — Framing layout, metric. A 10m wall run is framed at 0.4m (400mm) on-centre spacing, with a 2.4m stud/member length, plus a double top plate and single bottom plate (3 rows). Members = ⌊10 ÷ 0.4⌋ + 1 = 26. Stud material = 26 × 2.4m = 62.4m. Plate length = 10m × 3 = 30m. Total = 62.4m + 30m = 92.4m. With a 10% waste allowance, that's 101.64m, which at a 3.6m stock length rounds up to 29 pieces (104.4m bought, 2.76m left over).
Example 2 — Custom cut list. A shelving project needs four 2.4m shelves and six 1.2m brackets: total length = (2.4 × 4) + (1.2 × 6) = 9.6 + 7.2 = 16.8m. With 10% waste, that's 18.48m, which at a 3.6m stock length rounds up to 6 pieces (21.6m bought).
A frequent mistake is forgetting that lumber is sold in fixed stock lengths, so a raw total (like 18.48m) must be rounded up to whole pieces (6 × 3.6m = 21.6m), not left as a fractional figure. Another is skipping a waste allowance entirely, which often leaves a project just short after the first few cuts go wrong or a board is unusable. For framing specifically, a common error is treating the on-centre stud count as the total linear material needed — the stud count and the total length of plates (or joists, if applicable) are separate figures. Finally, using a single average density for all wood species can meaningfully over- or under-estimate weight, since density can vary by 50% or more between species like cedar and oak.
This calculator provides a material quantity, weight and cost estimate based on the lengths, spacing and density you enter. It does not check structural adequacy, allowable span, load capacity or local building code compliance — for a structural framing member, confirm sizing against a verified span table or a structural professional. Framing Layout does not add corner studs, king/jack studs around openings, or blocking. The Custom Cut List method totals length only and does not optimise how pieces are nested within stock lengths, so it may overestimate material compared to a carefully planned cut sheet. Weight estimates use typical average species densities, not your specific boards' measured density.
It depends on your project: for a framing run, enter the length and on-centre spacing; for a specific cut list, add each piece length and quantity. The calculator totals the length needed and rounds up to whole stock-length pieces, including a waste allowance.
Divide the wall run length by the on-centre spacing and add one for the starting stud (for example a 10ft wall at 16in spacing needs about 8 studs). Use the Framing Layout method above to calculate this automatically, plus optional top/bottom plates.
On-centre (OC) spacing is the distance measured from the centreline of one framing member to the centreline of the next, not the clear gap between them. Common residential spacings are 16 inches or 24 inches (400mm or 600mm).
Lumber weight depends on its dimensions and wood species density. Use the Weight tab above with your board's thickness, width, length and quantity, and select a species (or enter a custom density) for an estimate.
Weight equals volume multiplied by density: thickness × width × length × quantity gives volume, which is then multiplied by the wood species' density. Species density varies, so this is a typical-average estimate, not an exact figure for your specific boards.
Use the Framing Layout method with your wall's run length and chosen stud spacing (commonly 16in/400mm on-centre), and optionally add top and bottom plates. The calculator returns the stud count and total linear length needed.
5-10% is typical for straightforward framing runs, while more complex cut lists with many different lengths or angled cuts may need 10-15% to allow for offcuts and mistakes.
This varies by species, grade and dimension, and changes over time, so there's no single figure. Use the Cost tab above with your local supplier's price per piece or per linear foot/metre for an estimate specific to your project.
In North America, "lumber" usually refers to wood that has been milled into standard dimensional sizes (like a 2x4), while "timber" often refers to larger structural sections or is used more generally for wood as a building material, as is common in the UK and Australia.
No — it totals the length you need and divides by your stock length, which does not account for optimal cut-list nesting (arranging multiple short cuts within one stock length to minimise offcuts). For complex cut lists, a dedicated cut-optimisation tool may reduce material further.
No — a board foot is a unit of volume (144 cubic inches), while weight is that volume multiplied by the wood's density. This calculator's Weight tab estimates mass in kilograms or pounds, not board-foot volume; see our separate Board Foot Calculator for volume.