Math July 13, 2026 · 8 Min Read

Board Feet Calculator – Guide & Formulas

Calculate total board feet of lumber for woodworking and timber projects. Includes cost Estimations and waste factors.

Find the board footage (BF) of hardwood or softwood lumber. Input the thickness, width, and length of your boards to estimate total volume, costs, and project waste percentages.

Key Takeaway

Use the free Board Feet Calculator to calculate total board feet of lumber for woodworking and timber projects. includes cost estimations and waste factors. Get instant results with step-by-step explanations.

How to Use the Board Feet Calculator

  1. Enter the nominal or actual thickness and width of the board in inches.
  2. Enter the length of the board in feet or inches.
  3. Add the quantity of boards, board price per board foot, and waste factor.

The Formula

Board Feet = (Thickness_in * Width_in * Length_ft) / 12

Variable Definitions

  • BF: Board Foot (volume unit for lumber)
  • T_in: Thickness in inches
  • W_in: Width in inches
  • L_ft: Length in feet

Calculating Oak Planks for a Table

You need 6 rough-cut oak planks, each measuring 2 inches thick, 8 inches wide, and 10 feet long. Find the total board feet.

  1. Step 1: Set single board dimensions: T = 2 in, W = 8 in, L = 10 ft.
  2. Step 2: Apply the formula for one board: (2 × 8 × 10) / 12 = 160 / 12 ≈ 13.33 BF.
  3. Step 3: Multiply by quantity (6 boards): 13.33 × 6 = 80 board feet.
  4. Step 4: Add a 15% waste allowance (80 + 12 = 92 BF) to guarantee enough material.

Frequently Asked Questions

What is a board foot?

A board foot is a specialized unit of volume used for lumber in the United States and Canada. It is equal to the volume of a board that is 12 inches wide, 12 inches long, and 1 inch thick (144 cubic inches).

Does this calculator use nominal or actual dimensions?

Typically, board feet are calculated using the nominal (rough-sawn) dimensions, which are larger than the planed (surfaced) final dimensions.

What does "4/4" or "8/4" lumber mean?

Hardwood lumber is often sold in quarter-inch thickness intervals: "4/4" (four-quarter) is 1 inch thick, "5/4" is 1.25 inches thick, "8/4" is 2 inches thick, etc.