Lumber Calculator

1. Enter the total linear feet you need from your cut list.
2. Enter the stock length the lumber comes in.
3. Enter the thickness and width for board feet, and a price per piece.
4. Add a waste allowance and read the pieces, board feet and cost.

Here is what each result line means:

To price volume stock by the board foot instead, use the concrete formwork calculator for forming lumber, or the concrete slab calculator for the slab that lumber forms.

A lumber calculator turns the length of lumber you need into the number of pieces to buy. Framing lumber is sold by the piece in fixed stock lengths, so you cannot buy an exact linear figure; you buy whole boards and cut them down.

The tool adds a waste allowance, divides by the stock length and rounds up to whole pieces. It also totals the board feet and the cost, so you can compare buying in different stock lengths.

The linear feet you need are grossed up for waste, divided by the stock length and rounded up, because you buy whole boards. The board feet come from the cross-section times the length actually bought.

1. Add waste to the linear feet you need.
2. Divide by the stock length and round up for the pieces.
3. Multiply pieces by stock length for the linear feet bought.
4. Use the thickness and width for board feet, and the price for cost.

Choosing a stock length that divides your runs with little off-cut saves lumber. The tool assumes one stock length, so run it for each length to compare.

Suppose you need 240 linear feet of 2 by 4, buying 8 foot stock at 5.00 a piece, with 10 percent waste.

Calculation: 240 times 1.10 is 264 feet; divided by 8 is 33 pieces. That is 33 boards, 264 linear feet bought, about 176 board feet, and at 5.00 a piece roughly 165 in total.

The lesson: you always round up to whole boards, so the waste allowance and stock length drive the final count.

Stock Length

A stock length that matches your runs wastes less. An awkward length leaves long off-cuts that push the piece count up.

Waste Allowance

Off-cuts, defects and mistakes all add up. Ten to fifteen percent is usual; use more for a complex cut list or rough stock.

Cross-section

The thickness and width set the board feet, which matters when a yard prices by the board foot rather than the piece.

Mixed Lengths

Real jobs use several lengths. This tool assumes one; a cut-list optimizer squeezes more out of mixed stock.

Lumber is priced two ways, and the right tool depends on which.

Dimensional framing is usually sold by the piece, while rough hardwood is sold by the board foot. This tool reports both the pieces and the board feet so you can match either pricing.

Framing Takeoffs

Turn a run of studs, plates or joists into boards to buy.

Decking and Fencing

Count boards for rails, pickets or deck boards from the linear feet.

Comparing Stock Lengths

Run different stock lengths to see which wastes the least.

Budgeting

Get the piece count and cost before a trip to the yard.

1. Buying the Exact Linear Feet

You buy whole boards, not a linear total. Always round up to whole pieces.

2. Skipping Waste

Off-cuts and defects are real. Leaving out the allowance leaves you short before the job is done.

3. Ignoring Off-cut Length

A stock length that leaves a long, unusable off-cut wastes money. Match the stock to your runs.

4. Confusing Pieces and Board Feet

Pieces are for piece pricing; board feet are for volume pricing. Use the one your yard charges by.

5. Forgetting Defects

Some boards are too bowed or split to use. A waste allowance covers the ones you set aside.

The count is exact for a single stock length, but real jobs mix lengths and cuts, so treat it as a planning estimate and refine with a cut list.

Add your runs for the total linear feet, add waste, divide by the stock length and round up. For 240 feet in 8 foot stock with 10 percent waste, that is 33 pieces.

Divide the total linear feet, with waste, by the stock length and round up to whole boards. You cannot buy a part board, so always round up.

About 10 to 15 percent for off-cuts and defects. Use the higher end for a complex cut list, rough stock or an inexperienced crew.

Pick a length that divides your runs with little off-cut. Common stock is 8, 10, 12, 14 and 16 feet. Run the tool for each to compare waste.

Multiply thickness by width in inches by the total length bought in feet and divide by 12. The tool does this from the pieces and stock length.

Dimensional framing is usually sold by the piece. Rough and hardwood stock is sold by the board foot. Use the pricing your yard quotes.

No. It assumes one stock length. For mixed lengths, a cut-list optimizer packs the cuts to waste less across different boards.

That depends on the wall length and stud spacing. This tool counts pieces from linear feet; a stud calculator spaces studs along a wall.

Board feet usually use the nominal size you are charged by. For weight or a tight fit, use the actual milled size instead.

No. The calculation runs entirely in your browser and nothing you enter is stored or sent anywhere.

• USDA Forest Products Laboratory, Wood Handbook (wood measurement and properties).
• Oregon State University Wood Science: wood properties (lumber measurement and species data).
• BIA Technical Note 10, Dimensioning and Estimating Brick Masonry (Brick Industry Association; material estimating method).