Board Foot Calculator
Enter thickness, width, length and quantity to get board feet and cost.
What this tool does
A board foot is 144 cubic inches, a piece 1 inch thick, 12 inches wide and 12 inches long. Board feet = thickness (in) × width (in) × length (ft) ÷ 12. A 2 × 6 × 8 ft board is 2 × 6 × 8 ÷ 12 = 8 board feet.
Applies the board foot formula to a piece of lumber and multiplies by the quantity.
Prices the total at your cost per board foot.
How to use it
- Enter the thickness and width in inches.
- Enter the length in feet.
- Enter the number of pieces and a price per board foot.
- Read the board feet and the cost.
Why use this calculator
Calculates board feet from thickness, width and length, multiplies by the number of pieces and prices the total at your cost per board foot. Hardwood lumber is sold by the board foot, which is a volume, not a length. The conversion is simple but easy to botch with mixed units, and prices only make sense once you know the board feet.
Why we built it
We built the board foot calculator to turn thickness, width and length into board feet and cost for any number of pieces. Estimate the volume of other materials with the cubic yard calculator and compare prices with the unit price calculator.
Who this tool is for
- Woodworkers buying hardwood
- Furniture makers pricing a project
- Carpenters comparing lumber quotes
When to use it
- Buying hardwood from a lumber yard.
- Estimating the cost of a furniture project.
- Comparing prices between suppliers.
- Converting stock into volume.
How it works
Board feet = (thickness in inches × width in inches × length in feet) ÷ 12. Lumber is priced using the nominal thickness (for example, 4/4 is one inch), so use the quoted size, not the planed dimension.
Examples: 2 × 6 × 8 ft = 8 board feet. Three of them is 24 board feet; at 5 each the cost is 120.
Many suppliers round each board to the nearest quarter board foot, so a quote can differ slightly from the exact result.
A worked example
These are the values the calculator opens with, so you can see exactly what it does with them. Change any value on the page and the result updates; the figures below come from the same calculation.
| Input | Value |
|---|---|
| Currency symbol | $ (dollar) |
| Thickness | 2 |
| Width | 6 |
| Length | 8 |
| Number of pieces | 1 |
| Price per board foot | 0 |
With those inputs, the calculator returns:
- Board feet: 8
- Per piece: 8
- Cubic feet: 0.667
- Cubic metres: 0.0189
What you give it, and what you get back
| Item | Details |
|---|---|
| Thickness, width | In inches. |
| Length | In feet. |
| Pieces and price | Quantity and the price per board foot. |
| Output | Board feet per piece and in total, cubic feet, cubic metres, cost. |
Issues you may run into
| What you see | Why it happens | What to do |
|---|---|---|
| Length entered in inches | The length field is in feet. | Divide inches by 12. |
| Quote differs | Suppliers round and may charge for rough dimensions. | Ask which size they price on. |
| Metric lumber | Sizes are in inches and feet. | Convert millimetres to inches first. |
Assumptions and limitations
- Rectangular pieces.
- Uses the thickness you enter, not a planed size.
Frequently asked questions
What is a board foot?
A unit of lumber volume: 144 cubic inches, or a piece 1 inch thick, 12 inches wide and 1 foot long.
How do I calculate board feet?
Multiply thickness in inches by width in inches by length in feet and divide by 12.
How many board feet in a 2x4x8?
Using nominal size, 2 × 4 × 8 ÷ 12 = 5.33 board feet.
How many board feet in a cubic foot?
12 board feet.
Why is lumber sold by the board foot?
It is a volume measure that lets pieces of different sizes be priced fairly.
Is my information sent anywhere?
No. The calculation runs in your browser and nothing leaves the page.
Sources and accuracy
A board foot is a lumber volume unit equal to 144 cubic inches, that is a board 12 inches square and 1 inch thick, as defined in North American hardwood grading rules.
Figures last checked against the source on . Standards and rates can change — if you are relying on this for something that matters, confirm against the source above. Think a figure is wrong or out of date? Send a correction.