Use this calculator to calculate board-foot volume from lumber thickness, width, length, and piece count. Keep the default on Milled lumber for boards and slabs; switch to Log estimates only when you have a log's inside-bark small-end diameter and length.
Match the calculation to the lumber
The arithmetic is reliable only when the dimensions and tally convention describe the material actually being priced.
Worked example
- One board is 1.25 × 8 × 10 ÷ 12 = 8.33 ft.
- Five boards total 41.67 ft.
- At 8 per board ft, the geometric estimate is 333.33 before yard rounding, surfacing, freight, and tax.
Geometric volume versus invoice volume
Milled mode reports geometric volume from the dimensions entered. A lumberyard invoice may use rough thickness or another documented tally convention, so a mismatch does not by itself prove either number is wrong.
Log estimates are rule-specific
The three log outputs should be read by name. Do not average them or select the largest value; use the rule required by the buyer, contract, jurisdiction, or scaler.
Frequently asked questions
How do I calculate ?
Multiply thickness in inches by width in inches by length in feet, then divide by 12. Multiply that per-piece result by the number of identical pieces.
How many is a 2x4x8?
Using nominal 2 × 4 dimensions, the result is 5.33 ft. Using common dressed dimensions of 1.5 × 3.5 , the geometric volume is 3.5 ft. Use the basis required by the seller or the job.
What is the formula for a ?
With length in feet, = thickness in inches × width in inches × length in feet ÷ 12. With every dimension in inches, divide cubic inches by 144.
How do you calculate in a log?
A log rule uses inside-bark small-end diameter and log length to estimate recoverable lumber. Choose the rule required by the sale or scaler; Doyle, Scribner, and International 1/4-inch can return different totals.