Board Feet Calculator
Turn thickness, width, and length into board feet — for one board or a whole stack — and price the stock at your yard's rate.
The first number on every cut list
Rough lumber is priced by the board foot, so a project's material budget starts here. Measure each part's rough thickness, width, and length, add them up, and you know both how much wood to bring home and roughly what it will cost. Because a board foot bakes in thickness, 8/4 stock counts for twice the volume of 4/4 at the same footprint.
Once you have the net board feet, run them through the Lumber Cost Estimator to add a waste factor and price the whole project, or check how far a wide board will move with the Wood Movement Calculator.
Frequently Asked Questions
What is a board foot?
A board foot is the lumber trade's unit of volume: 144 cubic inches, or a piece one inch thick, twelve inches wide, and one foot long. Rough hardwood is sold by the board foot rather than by the linear foot, because a board foot accounts for thickness and width as well as length. The shop formula is thickness in inches times width in inches times length in feet, divided by twelve.
Do I use rough or planed thickness?
Use the rough, nominal thickness the yard bills by, not the final planed dimension. Hardwood is sold in quarters: 4/4 stock is a nominal one inch, 5/4 is an inch and a quarter, 8/4 is two inches, even though after surfacing the boards finish thinner. If you enter the planed thickness you will under-count the board feet — and under-budget the wood.
How much extra should I buy over the calculated amount?
Board feet tells you the volume of the boards themselves; it does not include waste. Once you know the net board feet for your project, add a waste factor — commonly 15 to 30 percent — for defects, snipe, checked ends, and the offcuts of breaking boards down to size. The Lumber Cost Estimator on this site does that step and prices the result.
Why is the price only an estimate?
Per-board-foot prices vary widely by species, grade, thickness, width, and supplier, and figured or wide boards often carry a premium. The figure here multiplies your board feet by the rate you enter, so it is only as accurate as that rate. Treat it as a planning number and confirm the current price with your lumber dealer before you buy.
Estimates only. Board-foot volume uses rough/nominal dimensions; prices vary by supplier and grade. Confirm the current rate with your lumber dealer before you buy.