Skip to main content
Calculator Answers

Board Foot Calculator

Blake Boege
Written by Blake Boege · Founder, Calculator Answers

A board foot calculator is a specialized wood volume utility used by woodworkers, contractors, and lumberyards to determine the volume of rough lumber. A board foot is a standard unit of volume equivalent to a board that is twelve inches wide, twelve inches long, and one inch thick. The calculator multiplies the lumber's thickness in inches, width in inches, and length in feet, dividing the result by twelve to find the total board feet. It can also estimate total material costs based on a specified price per board foot.

Enter thickness, width, length, and quantity. The calculator returns board feet per piece, the total for all pieces, and an optional total cost when you enter a price per board foot.

Quick Answer

Calculate the volume of lumber in board feet. Enter the thickness, width, length, and quantity to find the volume and total cost.

in

Nominal thickness in inches (1, 2, 4/4, 5/4, 8/4 boards). · e.g. 1

in

Nominal width in inches. · e.g. 6

Length unit

ft

e.g. 8

Number of pieces with these dimensions. · e.g. 10

$

Leave blank to skip the cost estimate. · e.g. 4.25

Board foot is a lumber volume unit equal to a 1 in × 12 in × 12 in block. The formula uses nominal dimensions.

Board feet

10 pieces

40

4 BF per piece

Board feet per piece4
Total board feet40
Length in feet8 ft

Add a small waste allowance (5 to 10 percent) when ordering if you plan to rip, joint, or trim the lumber.

Was this helpful?

Examples

1 in × 6 in × 8 ft, 10 pieces

4 BF per piece, 40 BF total

8/4 (2 in) × 8 in × 10 ft, 5 pieces

13.33 BF per piece, 66.67 BF total

1 in × 4 in × 6 ft, 24 pieces

2 BF per piece, 48 BF total

How it works

A board foot is 1 inch thick, 12 inches wide, 12 inches long (144 cubic inches of lumber). The standard formula uses thickness and width in inches and length in feet, divided by 12. Multiply by the number of pieces for the order total.

Board feet per piece · (thickness in × width in × length ft) ÷ 12

Total board feet · BF per piece × quantity

Estimated cost · total BF × price per BF

Length in inches? Divide by 144 instead of 12. The calculator handles both via the unit toggle.

Related home measurement calculators

Related Calculators

More tools from Home

Board and Batten CalculatorCalculate the number of boards and battens needed to cover a wall or build an accent wall, with precise spacing layouts.

Frequently asked questions

A board foot is a lumber volume unit equal to a piece 1 inch thick, 12 inches wide, and 12 inches long. One board foot is 144 cubic inches of lumber. It is used to price and order hardwood and rough-sawn lumber where boards come in random widths and lengths.

Board feet per piece equals thickness in inches multiplied by width in inches multiplied by length in feet, then divided by 12. Multiply by quantity for total board feet. If you measured length in inches, divide by 144 instead of 12 (because 12 × 12 = 144).

Board feet are almost always calculated with nominal (rough) dimensions, not the smaller actual dimensions after planing. A 1×6 board that is actually 3/4 inch by 5.5 inches is still billed as a 1×6 for board-foot purposes. Use the nominal dimensions when ordering lumber.

The cost estimate is total board feet multiplied by your entered price per board foot. It reflects only the lumber cost, not delivery, sales tax, surfacing or planing upcharges, kiln drying surcharges, or species premiums. Treat it as a planning figure and confirm with the supplier.

Yes, in most projects. Crosscutting to length and ripping to width produces offcuts. A common rule of thumb is to order 10 to 20 percent more lumber than the finished project requires. Order more for projects with lots of small parts, knot avoidance, or matched grain.

One board foot is 144 cubic inches. Multiplying thickness (in) by width (in) by length (in) gives volume in cubic inches; dividing by 144 converts to board feet. The shorter form (thickness × width × length-in-feet ÷ 12) is the same math: 12 inches per foot × 12 inches in the unit width cancels one factor of 12.