Lumber Calculator
Work out board feet, lineal feet and cost for dimensional lumber. Pick a nominal size or type your own thickness and width, enter the length and number of boards, set a price basis and a waste allowance, and get total and ordered board feet, lineal feet and cost — with by-size and by-length comparison tables and a downloadable PDF.
| Size | BF / board | Total BF | Cost |
|---|---|---|---|
| Enter a board to compare | |||
| Length | BF / board | Total BF | Cost |
|---|---|---|---|
| Enter a size to compare | |||
How to use the lumber calculator
Pick a nominal size or type your own thickness and width, enter the length and number of boards, set a price basis and a waste allowance, and get the total and ordered board feet, the lineal feet and the cost, with by-size and by-length comparison tables and a downloadable PDF.
Pick the board size
A common nominal size like 2×4, or type your own thickness and width in inches.
Enter length & count
The length of one board in feet, and how many identical boards you need.
Set price & waste
Price per board foot, lineal foot or per board, plus a waste allowance to order extra.
Read the result & save a PDF
See board feet, lineal feet and cost, compare sizes and lengths, and download it.
How board feet are calculated
A board foot is nominal thickness × nominal width × length ÷ 12. The catch is that it uses the nominal size — a 2×4 counts as 2 by 4 even though it measures 1.5 by 3.5 — while lineal feet and most prices use the actual length.
Worked example — ten 8 ft 2×6 boards, 10% waste
Board feet each: 2 × 6 × 8 ÷ 12 = 8 BF
Total board feet: 8 × 10 = 80 BF
Lineal feet: 8 × 10 = 80 ft
Order with 10% waste: 80 × 1.10 = 88 BF
Ten 8-foot 2×6 boards come to 80 board feet, or 88 board feet once you add 10% for waste — the amount to actually order.
Lumber size & board-feet charts
The numbers that come up most — nominal versus actual sizes, board feet per foot by size, and how board feet add up across the common stock lengths.
| Nominal | Actual size | BF per foot | 8 ft board |
|---|---|---|---|
| 2×4 | 1.5 × 3.5 in | 0.667 BF | 5.33 BF |
| 2×6 | 1.5 × 5.5 in | 1.00 BF | 8.00 BF |
| 2×8 | 1.5 × 7.25 in | 1.333 BF | 10.67 BF |
| 2×10 | 1.5 × 9.25 in | 1.667 BF | 13.33 BF |
| 2×12 | 1.5 × 11.25 in | 2.00 BF | 16.00 BF |
| 4×4 | 3.5 × 3.5 in | 1.333 BF | 10.67 BF |
Board feet use the nominal size even though the board dresses smaller — a 2×4 is figured as 2 by 4. Lineal feet and cut planning use the actual size.
| Length | 2×4 | 2×6 | 2×8 | 2×12 |
|---|---|---|---|---|
| 8 ft | 5.33 | 8.00 | 10.67 | 16.00 |
| 10 ft | 6.67 | 10.00 | 13.33 | 20.00 |
| 12 ft | 8.00 | 12.00 | 16.00 | 24.00 |
| 14 ft | 9.33 | 14.00 | 18.67 | 28.00 |
| 16 ft | 10.67 | 16.00 | 21.33 | 32.00 |
Board feet per board, before waste. The figures scale straight with length — double the length, double the board feet. Multiply by your board count for the total.
| Job type | Suggested waste | Why |
|---|---|---|
| Simple framing, straight cuts | 10% | Few off-cuts |
| Decking, fencing | 10–15% | Trim and spacing |
| Angled / mitered work | 15% | More off-cuts |
| Lower-grade / knotty stock | 15–20% | Cut around defects |
A starting guide, not a rule. Ordering a little extra is almost always cheaper than a second trip for one short board.
A lumber order comes from four things: the nominal size and the length set the board feet per board, the count scales it to the total, and the waste allowance gives the board feet and cost you actually order.
- Board feet use the nominal size — a 2×4 is figured as 2 by 4, not its 1.5 × 3.5 dressed size.
- Length and count are linear — both scale the board feet directly, so doubling either doubles the order.
- Waste is what you actually buy — add 10–15% so you’re not short, and round up to stock lengths.
Everything the calculator works out
One set of inputs gives you the board feet per board and in total, the lineal feet, the order quantity with waste and the cost — plus a comparison across sizes and lengths, and a report to save.
The figures behind every order
Built for anyone buying or estimating lumber
A deck, a wall, a fence, a workshop build — the board feet decide the order and the cost, and getting them right keeps you from a short pile or a garage full of leftovers. A quick estimate before the lumberyard trip saves time and money.
Building a deck, fence or shed, and needing to know how much lumber to buy and what it will cost before the trip to the yard.
- Board feet and cost
- Compare sizes and lengths
- Add waste so you’re not short
Pricing a framing job and doing material takeoffs, where board feet per size drive the order and the bid.
- Total board feet for the order
- Cost per board foot
- Save the PDF to the bid
Buying hardwood by the board foot for furniture and shop projects, where accurate board feet keep the cost in check.
- Board feet for a cut list
- Compare by size and length
- Allow extra for figure and defects
7 tips for estimating lumber
The things that throw off a lumber order — and the checks that keep your board-foot count and your budget honest.
Lumber calculator FAQ
The board-foot, sizing and pricing questions people ask most when ordering dimensional lumber.
Board feet equal nominal thickness in inches times nominal width in inches times length in feet, all divided by 12. So an 8-foot 2×6 is 2 × 6 × 8 ÷ 12, which is 8 board feet.
The key is to use the nominal size, not the smaller dressed size — a 2×4 is figured as 2 by 4 even though it actually measures 1.5 by 3.5 inches. The calculator does this for any size and length, and multiplies by your board count.
A board foot is a measure of volume — 144 cubic inches, or a piece 1 inch thick by 12 inches wide by 1 foot long. A lineal (or running) foot is just a measure of length, one foot, regardless of the board’s thickness or width.
Board feet are the trade unit for buying and pricing lumber in bulk, while lineal feet and per-board pricing are common at home centers. The calculator gives both so you can match whichever basis your supplier uses.
The 2×4 is the nominal size — the rough dimension before the board is dried and planed smooth. After surfacing, a 2×4 actually measures about 1.5 by 3.5 inches, and the larger widths lose a bit more, so a 2×10 dresses to 1.5 by 9.25.
Board feet are still figured from the nominal size, which is how lumber has always been sold. The calculator shows both the nominal and the actual dressed size so you can plan cuts and spacing accurately.
A 2×4 holds 0.667 board feet per foot of length, so an 8-foot 2×4 is about 5.33 board feet, a 10-foot one about 6.67, and a 12-foot one 8 board feet.
That comes straight from 2 × 4 ÷ 12, which is 0.667 board feet per lineal foot. Wider boards hold more: a 2×6 is 1 board foot per foot, and a 2×12 is 2. The by-size table shows every common size at your length.
A 10 percent waste allowance is a common starting point for straightforward work, covering cut-offs, the odd defect and small mistakes. For complex cuts, angled work, or lower-grade stock with more knots and splits, bump it to 15 percent or more.
Ordering a little extra is almost always cheaper than making a second trip or pausing a job for one short board. The calculator adds your waste percentage to the order board feet and the cost, while keeping the base board feet separate.
All three are used. Lumberyards and hardwood dealers usually price by the board foot, which fairly reflects the volume of wood. Home centers often tag dimensional lumber by the lineal foot or simply per board, which is easier for shoppers.
The right basis depends on where you buy. The calculator lets you choose per board foot, per lineal foot or per board, and applies the waste allowance, so you can compare quotes on the same footing.
Yes — board feet scale directly with length. A 2×6 is 1 board foot per lineal foot, so an 8-foot piece is 8 board feet and a 16-foot piece is 16. Double the length, double the board feet.
Thickness and width set the board feet per foot; length then multiplies it. The by-length table shows how the same size adds up across the common 8, 10, 12, 14 and 16-foot stock lengths so you can pick the most efficient cut.
Lumber comes in fixed stock lengths, usually even 2-foot increments, so you often buy a little more than the exact figure once you round up to what’s on the rack. Grade, moisture and how much you can nest your cuts also change how far the wood goes.
The calculator gives an accurate board-foot and cost estimate from your sizes and waste allowance. Treat it as a buying guide, round up to stock lengths, and confirm the current price with your supplier before ordering.
Estimate Only — Buy a Little Extra: This calculator finds board feet as nominal thickness in × nominal width in × length ft ÷ 12. A 2×4 is figured as 2 × 4 even though it dresses to 1.5 × 3.5 inches; lineal feet and most retail prices use the actual length. Order board feet and cost include your waste allowance, while the base board feet do not. Lumber comes in fixed stock lengths and prices change often, so round up to what’s on the rack. For reference and estimating only; round up to stock lengths and confirm the current price with your supplier before ordering.