Lumber Calculator

Calculate the exact number of board feet (BF) or linear feet (LF) needed for your woodworking or framing project, and estimate total material costs instantly.

Quantity pieces Please enter a positive number

Length per piece feet Please enter a positive number

Thickness inches Nominal thickness (e.g., 2 for a 2x4) Please enter a valid thickness

Width inches Nominal width (e.g., 4 for a 2x4) Please enter a valid width

Waste buffer %

Accounts for cut-offs and bad grain Please enter a valid percentage

Cost per Board Foot (Optional) $/BF Please enter a valid price

Calculation Results

Total Volume

— Board Feet (BF)

Includes your requested waste buffer.

How to use this lumber calculator

Enter board dimensions

Input the thickness and width in inches, and the length in feet. Use the nominal sizes (e.g., 2 and 4 for a 2x4) when purchasing dimensional framing lumber.

Specify the quantity

Enter the total number of boards you need for this specific dimension to calculate your total volumetric requirement.

Set your waste and price

A 10% waste buffer is standard for accommodating saw cuts and wood defects. If you know the price per board foot ($/BF) from your lumber yard, enter it to estimate the cost.

Review the takeoff

The tool instantly calculates the total board feet (the volume of the wood) and the total linear feet (the straight-line length of the wood).

Board Foot Calculations for Common Framing Lumber (Qty: 100 pieces)

Lumber Size (Nominal)	Board Length	Total Linear Feet	Total Board Feet (100 pcs)
2x4	8 ft	800 LF	533.333 BF
2x4	10 ft	1,000 LF	666.667 BF
2x4	12 ft	1,200 LF	800 BF
2x4	14 ft	1,400 LF	933.333 BF
2x4	16 ft	1,600 LF	1,066.667 BF
2x4	20 ft	2,000 LF	1,333.333 BF
2x6	8 ft	800 LF	800 BF
2x6	10 ft	1,000 LF	1,000 BF
2x6	12 ft	1,200 LF	1,200 BF
2x6	14 ft	1,400 LF	1,400 BF
2x6	16 ft	1,600 LF	1,600 BF
2x6	20 ft	2,000 LF	2,000 BF
2x8	8 ft	800 LF	1,066.667 BF
2x8	10 ft	1,000 LF	1,333.333 BF
2x8	12 ft	1,200 LF	1,600 BF
2x8	14 ft	1,400 LF	1,866.667 BF
2x8	16 ft	1,600 LF	2,133.333 BF
2x8	20 ft	2,000 LF	2,666.667 BF
2x10	8 ft	800 LF	1,333.333 BF
2x10	10 ft	1,000 LF	1,666.667 BF
2x10	12 ft	1,200 LF	2,000 BF
2x10	14 ft	1,400 LF	2,333.333 BF
2x10	16 ft	1,600 LF	2,666.667 BF
2x10	20 ft	2,000 LF	3,333.333 BF

Frequently asked questions

What is a board foot?

A board foot is a volume measurement of lumber equal to 144 cubic inches. It represents a piece of wood that is 12 inches wide, 12 inches long, and 1 inch thick. Hardwood is almost exclusively sold by the board foot rather than by the linear foot.

How many board feet are in a 2x4?

An 8-foot 2x4 contains exactly 5.33 board feet. Even though a modern, kiln-dried 2x4 is actually milled down to 1.5" × 3.5", board footage for softwoods is traditionally calculated using the original nominal dimensions before surfacing.

Why do hardwood sellers use 4/4 or 8/4 sizing?

Hardwood thickness is traditionally measured in quarters of an inch. Therefore, 4/4 ("four-quarter") means 1 inch thick, 6/4 means 1.5 inches thick, and 8/4 means 2 inches thick. When using this calculator, simply enter the decimal equivalent (1, 1.5, or 2) in the thickness field.

Should I use nominal or actual dimensions?

When buying mass-produced softwoods (like a 2x4 or 4x4 from a hardware store), use the nominal dimensions (e.g., 2 and 4). When buying rough-sawn hardwood from a specialty lumber yard, you must measure and use the actual, exact dimensions of the rough boards to calculate the true board footage.

About this calculator

This lumber calculator helps woodworkers, carpenters, and DIYers translate board dimensions into accurate purchasing volumes. Understanding the difference between Board Feet (volume) and Linear Feet (length) is crucial, as premium woods are priced by their total volume.

The mathematical formulas used in this estimator are:

Board Feet (per piece) = (Thickness (in) × Width (in) × Length (ft)) ÷ 12

Base Board Feet = Board Feet (per piece) × Quantity
Total Board Feet = Base Board Feet × (1 + (Waste % ÷ 100))

Linear Feet = Length (ft) × Quantity

Planning for waste: Purchasing rough lumber requires milling (jointing and planing) to achieve square edges and flat faces. This process removes material. We recommend a 10% to 15% waste buffer for standard lumber, and up to a 20% to 30% buffer if you are working with heavily knotted or warped rough-sawn wood.