What this calculator does
Lumber weight works out weight of dimensional lumber or a stack of boards, from species density and count. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaBoard volume (ft³) = (thickness/12) × (width/12) × length; weight = volume × species density × board count
The inputs explained
| Field | What to enter |
|---|---|
| Species | Choose from Douglas fir, kiln-dried (34 lb/ft³), Southern yellow pine, kiln-dried (36 lb/ft³), Spruce-pine-fir, kiln-dried (29 lb/ft³), Western red cedar (23 lb/ft³), Redwood (28 lb/ft³), Red oak (44 lb/ft³), Hard maple (45 lb/ft³), Poplar (28 lb/ft³). |
| Board thickness (in) | A number, measured in in. Starts at 1.5. |
| Board width (in) | A number, measured in in. Starts at 5.5. |
| Board length (ft) | A number, measured in ft. Starts at 8. |
| Number of boards | A number. Starts at 1. |
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
How the answer changes with board thickness
Every other input is held at the calculator’s starting values while board thickness varies. Select any row to load that scenario into the calculator.