- Free board foot calculator
- Multiple lumber sizes
- Cost estimate option
Board Foot Calculator
Use this board foot calculator to calculate board feet for lumber from thickness, width, length, and quantity. Add several lumber sizes in one estimate, include optional waste, use US or metric dimensions, and calculate an estimated lumber cost when you know the price per board foot.
Board feet = thickness (in) × width (in) × length (ft) ÷ 12 × quantity.
Board Foot Calculator
Calculate board feet for lumber using thickness, width, length, and quantity. Add multiple lumber sizes and include an optional waste allowance.
How to Use the Board Foot Calculator
Enter the lumber dimensions and quantity, then let the calculator total the board footage for each item and the whole project.
Enter thickness
Add the actual lumber thickness and choose the correct unit. You can use inches, feet, centimeters, meters, or millimeters.
Enter width and length
Type the board width and length. Each dimension has its own unit selector, so mixed units are supported.
Add quantity and lumber sizes
Set the number of boards, then add another lumber size if your project uses more than one dimension.
Review board feet and cost
The calculator totals the base and final board feet. You can also add waste and optionally estimate material cost.
Board Foot Formula and Calculation
A board foot is a unit of lumber volume, not surface area. One board foot equals 144 cubic inches.
Use thickness and width in inches, length in feet, and multiply by quantity.
- T = thickness in inches
- W = width in inches
- L = length in feet
- Q = number of boards
A 1-inch × 12-inch × 12-inch piece contains 144 cubic inches. When length is entered in feet, dividing thickness × width × length by 12 converts the dimensions into board feet.
Board Feet Calculation Examples
These common lumber examples show how the board feet formula works.
1 × 6 × 8 ft board
1 in × 6 in × 8 ft ÷ 12 × 1
4.00 board feet2 × 8 × 10 ft board
2 in × 8 in × 10 ft ÷ 12 × 1
13.33 board feetTen 1 × 8 × 8 ft boards
1 in × 8 in × 8 ft ÷ 12 × 10
53.33 board feetBoard Foot Calculator for Lumber
Board feet are widely used to measure the volume of rough and dimensional lumber. A lumber board foot calculator is useful when several boards have different thicknesses, widths, lengths, or quantities because each item can be calculated separately and then added into one lumber estimate.
How to Calculate Board Feet of Lumber
Measure the board thickness and width, record the length, and apply the board foot formula. If your dimensions use metric units, the calculator converts them internally before performing the board foot calculation. This helps avoid manual conversion errors when working with centimeters, meters, or millimeters.
Board foot cost calculator
If your supplier gives a price per board foot, enable the optional cost estimate in the calculator and enter the price. The total cost is calculated from the final board footage, including any waste allowance you choose to add. This makes the tool useful as a lumber cost calculator or lumber price calculator for simple material budgeting.
Using waste for woodworking projects
Extra lumber may be needed for defects, grain matching, trimming, cut loss, and project-specific selection. The correct allowance depends on the material and project, so use the waste field only when it reflects your actual planning needs.
Board feet vs. square feet
Board feet and square feet measure different things. Board feet measure lumber volume, while square feet measure surface area. A direct conversion between board feet and square feet requires a known thickness because the third dimension affects volume.
Board Foot and Lumber Measurement Reference
These values help explain how board footage relates to common lumber measurements.
| Measurement | Equivalent | Meaning |
|---|---|---|
| 1 board foot | 144 cubic inches | Lumber volume |
| 1 board foot | 1 in × 12 in × 12 in | Reference board-foot volume |
| 1 cubic foot | 12 board feet | Volume conversion |
| Board feet → square feet | Depends on thickness | Area cannot be determined without thickness |
Frequently Asked Questions
Quick answers about board feet, lumber dimensions, pricing, and conversions.
How do you calculate board feet?
Multiply thickness in inches by width in inches by length in feet, divide by 12, then multiply by the number of boards.
What is one board foot?
One board foot is 144 cubic inches of lumber, commonly represented by a piece 1 inch thick, 12 inches wide, and 12 inches long.
Can I calculate multiple lumber sizes at once?
Yes. Use “Add Another Lumber Size” for each different dimension. The calculator totals all items into one final board-foot estimate.
Can I estimate lumber cost from board feet?
Yes. Enable the optional cost estimate, enter the price per board foot, and choose the currency. The final cost is based on the total board feet after waste.
Can I use metric measurements?
Yes. Thickness, width, and length can each be entered in inches, feet, centimeters, meters, or millimeters.
Are board feet and square feet the same?
No. Board feet measure volume, while square feet measure area. Thickness is needed if you want to relate board-foot volume to surface area.
Can I use this as a log board foot calculator?
No. This calculator uses lumber dimensions. Log board-foot estimates may use log-scaling rules such as Doyle or International, which require a different calculation method.
Useful Lumber and Project Calculators
Use related tools when you need area, volume, or project-specific material estimates.