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Lumber cost calculator

Lumber is priced three different ways: per board foot, per linear foot and per piece. Enter up to three boards however they are priced, and see each one converted to all three, plus what it costs to cover your job with whole boards.

Inputs

Boards to compare (thickness and width in inches, length in feet)
Clear a board's price to leave it out of the comparison. The prices filled in are examples, not current prices from any store.

Cheapest for this job

$55.72

2×4×8: 14 boards to cover 100 linear feet plus 10% waste (110 ft). Lowest price per board foot: 2×4×8 at $0.75.

BoardPer BFPer lin. ftPer pieceBoardsSurplusJob total
2×4×8 ✓$0.75$0.50$3.981412 ft$55.72
2×4×10$0.82$0.55$5.481110 ft$60.28
2×4×12$0.87$0.58$6.981020 ft$69.80

Surplus is length bought beyond the job before waste: it is your waste allowance plus the rounding up to whole boards.

Three ways to price the same board

Hardwood dealers price by the board foot, a volume of 144 cubic inches. Moulding, trim and many softwood boards are priced by the linear foot, which ignores width and thickness. Home centres price dimension lumber per piece. None of these can be compared with another until they are converted, and the conversion depends only on the board's size:

  • board feet per linear foot = thickness × width / 12 (inches)
  • board feet per piece = thickness × width × length(ft) / 12
  • price per linear foot = price per BF × BF per linear foot
  • price per piece = price per BF × BF per piece

The calculator turns whatever price you enter into a price per board foot, then derives the other two from it. For the job total it divides the linear feet you need (plus waste) by the board length, rounds up to whole boards, multiplies by the price per piece and adds tax.

Worked example

The defaults compare 2×4s at example prices of $3.98 for 8 ft, $5.48 for 10 ft and $6.98 for 12 ft, for a job that needs 100 linear feet plus 10% waste, so 110 feet.

  • 8 ft boards: 110 / 8 = 13.75, so 14 boards, $55.72, which is $0.50 per linear foot
  • 10 ft boards: exactly 11 boards, $60.28, which is $0.55 per linear foot
  • 12 ft boards: 110 / 12 = 9.17, so 10 boards, $69.80, which is $0.58 per linear foot

At these prices the shortest board is cheapest per foot and for the job: $4.56 less than the 10-footers and $14.08 less than the 12-footers, which also leave 20 feet of surplus against 12 for the 8-footers and 10 for the 10-footers. That only holds if the parts can be cut from 8 ft boards. For wall studs or deck joists that must be one piece, the part length decides the board length and this comparison does not apply.

A hardwood price, three ways

What $10.00 per board foot works out to for a few common rough hardwood boards:

BoardBF per piecePer linear ftPer piece
4/4 × 6" × 8'4.00$5.00$40.00
4/4 × 8" × 10'6.67$6.67$66.67
8/4 × 6" × 8'8.00$10.00$80.00

Where it stops being reliable

  • Linear feet are not interchangeable. The job total assumes the parts can come from any board. With fixed part lengths, count boards with the cut list optimizer first.
  • Grade and species are not in the arithmetic. A cheaper board that needs more culling or has more defects can cost more in the end. Compare like with like.
  • Prices change. The defaults are illustrations. Use the prices on the tag or quote in front of you, and check whether a quote already includes delivery or tax.

This is a price comparison, not purchasing advice: it has no view on which store, species or grade you should buy.

Common questions

How do I convert a price per board foot to a price per linear foot?

Multiply by the board feet in one linear foot, which is thickness × width / 12 with both in inches. A 1 × 6 has 0.5 board feet per foot, so $8.00 per board foot is $4.00 per linear foot. Going the other way, divide.

Is a longer board cheaper per foot?

Sometimes, often not. Longer dimension lumber usually costs a little more per foot because long straight trees are scarcer. What matters for a job is the cost of the boards you actually have to buy, including the leftover from rounding up to whole boards, which is what the job total column shows.

Which size do I use for board feet on dimension lumber?

The nominal size. A 2x4 is tallied as 2 × 4, which is 0.667 board feet per foot, even though it measures 1 1/2 × 3 1/2. Board-foot prices for softwood are quoted on that basis. Hardwood is tallied on its rough thickness in quarters and its measured width.

Does the linear-foot total mean I can use every foot?

Only if your pieces can come from any board. If you need 9-foot pieces, an 8-foot board is useless whatever it costs per foot. When pieces have fixed lengths, run them through the cut list optimizer with each stock length to see how many boards each option really needs, then price those counts here.

Why is tax a separate box?

Because some quotes include it and some do not, and because a per-board-foot comparison is fairer before tax. Leave it at zero to compare shelf prices.

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