Lumber Weight Calculator
Calculate the weight of lumber: enter board feet and wood density to get total weight, using 1 board foot = 1/12 cubic foot.
How this calculator works
Lumber is priced and measured in board feet, but a board foot is a volume, not a weight. To get weight, you need to know how much wood you have and how heavy that wood is per unit of volume. This calculator takes the board feet you enter and the density you pick, then converts the two into a total weight in pounds.
The key conversion is that one board foot equals 1/12 of a cubic foot. So the calculator turns your board feet into cubic feet, then multiplies by the density to give the final weight.
Formula: Weight = board feet × (1/12 cubic foot) × density.
Kiln-dried softwood is about 35 lb per cubic foot; denser hardwoods and green (wet) lumber weigh more.
Worked example
100 board feet of softwood at 35 lb/ft³:
- Board feet: 100
- Density: 35 lb/ft³
- Weight: 100 × (1/12) × 35 ≈ 291.67 lb
Notes
The density you enter drives the result, so it is worth matching it to your actual stock. Green lumber, cut but not yet dried, can weigh roughly 50% more than kiln-dried lumber of the same species, because it still holds a large amount of water.
Hardwoods sit well above softwoods on the density scale. Species like oak typically run in the range of 45 to 55 lb per cubic foot, compared with about 35 for common kiln-dried softwood. Treat these as general ranges, not exact figures — the right number depends on the species, grade, and moisture of the wood in front of you.
How to use
Enter the total board feet for your lumber and choose a density that matches the wood type and condition. Read off the total weight in pounds. If your order mixes species or dry and green stock, run each group on its own and add the results for a full picture of what you will be handling.
Weights are estimates based on typical densities. Actual weight varies with moisture, mix design, and material grade — confirm with your supplier.
Frequently asked questions
What is a board foot?
A board foot is a unit of lumber volume, not a measure of length or area. One board foot equals 1/12 of a cubic foot — the amount of wood in a piece that is one foot long, one foot wide, and one inch thick. Board feet let you compare and price boards of different sizes on a common volume basis.
Why does the same board weigh different amounts?
Wood weight depends mostly on species and moisture. Green, freshly cut lumber still holds a lot of water, so it weighs noticeably more than the same board once it has been kiln-dried. Dense hardwoods also weigh more than lightweight softwoods. Because of this, the density you enter has a large effect on the total.
What density should I enter?
Kiln-dried softwood such as pine, fir, or spruce runs around 35 pounds per cubic foot, which is a common default. Denser hardwoods like oak sit higher, and green or wet lumber is heavier still. If your supplier lists a density or moisture grade for your stock, use that figure for the closest estimate.
Does this account for treated or wet lumber?
Only through the density you enter. Pressure-treated and green lumber both carry extra water and chemicals that add weight, so they call for a higher density value than dry stock. If you are estimating freshly treated boards, expect them to weigh more than the kiln-dried figure and raise your density input accordingly.
Estimates only. Verify quantities with your supplier before purchasing.