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Board Feet Calculator
Board Feet Calculator
Material Calculators

Board Feet Calculator

Calculate board feet and lumber cost from thickness, width, and length.

Formula: Board Feet = (Thickness × Width × Length) ÷ 12

DIY difficulty

EasyTypical time: Varies by project
  • ›Mainly measuring, marking, and cutting to length
  • ›Difficulty depends on the project — a simple shelf vs. a cabinet are very different

Must-have tools

Tape measureCircular saw or miter sawSafety glasses

How to calculate board feet for lumber

  1. Enter the board thickness in inches — 1 inch is standard for most hardwood, 1.5 inches for dimensional lumber like a 2×4.

  2. Enter the width in inches and length in feet. For a 1×6×8 board, that's 1, 6, and 8.

  3. Set the number of pieces you need. The calculator multiplies everything out and divides by 12 to get board feet.

  4. Add a price per board foot to get a total material cost estimate. Hardwood dealers price by board foot; big-box stores typically price by the linear foot instead.

Common uses

  • Ordering hardwood from a sawmill or specialty dealer
  • Estimating material cost for a woodworking or furniture project
  • Planning lumber quantities for finish carpentry or trim

Frequently asked questions

What exactly is a board foot?
A board foot is a volume unit equal to 1 foot × 1 foot × 1 inch thick, or 144 cubic inches. It's the standard way hardwood dealers sell rough-sawn lumber.
Do Home Depot and Lowe's sell lumber by the board foot?
Usually not — big-box stores price dimensional lumber by the linear foot. Board foot pricing is more common at hardwood dealers, sawmills, and specialty lumberyards.
How much waste should I account for in a lumber project?
For rough-sawn hardwood, add 20–30% for defects, planer waste, and off-cuts. For dimensional framing lumber, 10–15% is usually plenty.
What's the difference between rough-sawn and S4S lumber?
Rough-sawn is cut at the mill with no further surfacing — actual dimensions match nominal. S4S (surfaced four sides) is planed smooth, so a 1×6 S4S is actually 3/4" × 5.5". Always use actual dimensions for structural calculations.
How do I convert board feet to linear feet?
Multiply board feet by 12, then divide by (thickness × width in inches). Example: 10 BF of 1×6 = (10 × 12) ÷ (1 × 6) = 20 linear feet.

Common mistakes to avoid

  • ✕Confusing board feet with linear feet — board feet measure volume; big-box stores price by the linear foot.
  • ✕Not accounting for defects in rough-sawn lumber — knots and splits add up. Add 20–25% when buying from a sawmill.
  • ✕Forgetting nominal vs. actual size — a 1×6 is actually 3/4" × 5.5" surfaced. Use actual dimensions in structural math.
  • ✕Buying from multiple batches — color and grain vary between mill runs. Buy all visible-surface lumber from the same run.

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Not sure whether to DIY this project?

Read our project-by-project guide on when to hire a contractor vs. do it yourself.

Read the guide →

About this calculator

Enter the thickness, width, length, and number of pieces to get total board feet and estimated cost.

All results are estimates. Verify quantities with your local supplier and confirm measurements before purchasing materials. Requirements vary by region and project type.

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