Lumber Calculator

How to Use the Lumber Calculator

The board foot is the standard unit for buying and selling hardwood lumber and specialty wood. Enter the board thickness in inches, the width in inches, and the length in feet. The calculator computes the board feet per piece using the formula: board feet equals thickness times width times length divided by 12. Enter a quantity to calculate total board feet for multiple pieces, and optionally enter a price per board foot to see the cost per piece and total cost.

When purchasing lumber from a hardwood dealer, prices are quoted per board foot rather than per linear foot. This calculator helps you compare costs across different sizes and species. For dimensional softwood lumber sold at home improvement stores, the price is typically listed per linear foot or per piece, so board foot pricing is less relevant for those purchases.

Understanding Board Feet

One board foot represents a volume of 144 cubic inches of wood, equivalent to a board measuring 1 inch thick, 12 inches wide, and 1 foot long. A 2x6 board that is 10 feet long contains (2 x 6 x 10) / 12 = 10 board feet. The board foot measurement uses nominal dimensions for thickness and width, not the actual milled dimensions. This means a nominal 1-inch board that has been planed to 3/4 inch is still calculated as 1 inch thick for pricing purposes.

Nominal vs Actual Lumber Dimensions

Dimensional lumber sold at retail stores uses nominal sizes that differ from the actual dimensions. A 2x4 actually measures 1.5 inches by 3.5 inches. A 2x6 is 1.5 by 5.5 inches. A 1x6 is 0.75 by 5.5 inches. When calculating board feet for purchasing hardwood from a mill, use the rough-sawn thickness, which is usually sold in quarter-inch increments as 4/4, 5/4, 6/4, 8/4, and so on, where 4/4 equals one inch thick.

Common Lumber Species and Pricing

Softwood species like pine, spruce, and fir are the most affordable and commonly used for framing and general construction. Poplar is an inexpensive hardwood suitable for painted projects. Red and white oak are mid-range hardwoods popular for furniture and cabinetry. Hard maple is prized for its durability and light color. Walnut, cherry, and mahogany are premium species that command higher prices but offer exceptional beauty and workability for fine woodworking projects.

Frequently Asked Questions

What is a board foot?

A board foot is a standard unit for measuring lumber volume equal to 144 cubic inches, or a piece of wood 1 inch thick, 12 inches wide, and 12 inches long. The formula is thickness in inches times width in inches times length in feet divided by 12.

How do I calculate board feet?

Multiply the thickness in inches by the width in inches by the length in feet, then divide by 12. For multiple pieces, multiply the board feet per piece by the quantity.

What is the difference between nominal and actual lumber size?

Nominal size is the label, such as 2x4, while the actual size after drying and planing is 1.5 by 3.5 inches. When calculating board feet for purchasing, use nominal dimensions as that is how lumber is priced.

How much does lumber cost per board foot?

Prices vary by species and market. Softwoods range from $2 to $5, common hardwoods from $4 to $10, and exotic species from $8 to $20 or more per board foot.

How do I convert linear feet to board feet?

Multiply the linear feet by the thickness and width in inches, then divide by 12. For example, 10 linear feet of 1x6 equals 5 board feet.