Home / Lumber
Board Foot Calculator
Add up lumber in board feet or cubic metres: one row per size, with quantity, and the total cost from a price per board foot or per cubic metre.
Board Foot Calculator: A board foot is 144 cubic inches, a piece 12 in wide, 12 in long, and 1 in thick. For each row the tool multiplies thickness (in) by width (in) by length (ft), divides by 12, and multiplies by the quantity; in metric it gives cubic metres. One board foot is 0.00236 m³. Runs 100% locally in your browser with zero server file uploads.
- Category
- Home & family tools
- Runs
- In your browser
- Cost
- Free · no sign-up
- Availability
- Ready to use
Runs entirely in your browser
| Thickness (in) | Width (in) | Length (ft) | Quantity | bd ft | |
|---|---|---|---|---|---|
| 53.33 | |||||
| 20 |
A board foot is 12 × 12 × 1 inches, 144 cubic inches. Board feet = thickness (in) × width (in) × length (ft) ÷ 12. Hardwood is sold by its rough, nominal thickness, so a 4/4 board counts as 1 inch even when planed thinner; softwood such as a 2×4 is usually counted by its nominal size too.
Worked examples
Ten 2×4s, 8 ft long: 2 × 4 × 8 ÷ 12 × 10 = 53⅓ board feet. Four 1×6 boards, 10 ft long: 1 × 6 × 10 ÷ 12 × 4 = 20 board feet. Together, 73⅓ board feet, or 0.173 m³.
For a sloped roof's rafters, the roof pitch calculator gives their length from the run.
Waste
Add extra for offcuts, knots, and splits, more for hardwood that has to be ripped and planed than for framing lumber cut to length.
How to use it
- Choose inches and feet, or millimetres and metres.
- Enter each size's thickness, width, length, and quantity; add rows as needed.
- Read the total volume and, with a price, the cost.
Privacy & limitations
Everything is worked out in your browser.
Related tools
Frequently asked questions
How many board feet is a 2×4 that is 8 feet long?
2 × 4 × 8 ÷ 12 = 5⅓ board feet, using the nominal size, as lumberyards usually do.
Why use nominal rather than actual sizes?
Lumber is priced by its size before drying and planing, so a 2×4 that measures 1½ × 3½ in is still counted as 2 × 4. Hardwood is sold by quarters of an inch of rough thickness: 4/4 is 1 in, 8/4 is 2 in.
How do I convert board feet to cubic metres?
Multiply by 0.00236; one cubic metre is about 424 board feet.
Free tool · runs in your browser · no account required