Board Foot Calculator

How to calculate board feet

1. Enter one board’s thickness, width and length, checking each field’s unit. Inch fields accept 3/4 or 1 1/2; use decimals for feet and metric units.
2. Set the number of identical boards. Use 1 for a single piece. Different sizes need separate calculations.
3. Read the total board feet. Open Calculation details for per-board volume and cubic equivalents. Confirm the dimension basis before comparing a supplier tally.

Board feet measure volume

One board foot is 144 cubic inches: a piece 1 inch thick, 12 inches wide and 12 inches long. It equals one twelfth of a cubic foot, or 0.002359737216 m³. It measures volume, not area or length.

With thickness and width in inches and length in feet, multiply thickness × width × length × count and divide by 12. With all three dimensions in inches, divide by 144.

Each dimension has its own unit. Metric and mixed-unit entries are converted using 1 inch = 0.0254 m and 1 foot = 0.3048 m. Changing a selector reinterprets the retained value; it does not convert it.

Use measured sizes to estimate physical volume. Supplier billing may use a different basis. The calculator does not infer finished sizes from 2×4 or treat a 5/4 stock label as a measurement. The numeric fraction 5/4 alone equals 1.25 inches.

Worked lumber-volume examples

A board 1 in thick, 6 in wide and 8 ft long contains 4 board feet. Four identical boards contain 16 board feet, equivalent to 0.037755795456 m³ before display rounding.

A measured board 1.5 in × 3.5 in × 8 ft contains 3.5 board feet. Twenty identical pieces contain 70 board feet. These measurements are entered directly, not inferred from a nominal label.

A 3/4 in × 6 in × 8 ft board contains 3 board feet. Entering 25.4 mm × 15.24 cm × 2.4384 m for four boards gives 16 board feet, the same as the first example.

Entered dimensions and supplier tallies

This is a volume calculation for identical boards. It does not price orders, add waste, mix sizes, plan cuts, determine stock lengths or estimate log yield.

Rough or dressed sizes, minimum billed thickness, surface measure and commercial length rounding are supplier-specific. Cubic equivalents describe the entered basis and do not prove finished-stock volume when billing dimensions were used.

Your measurements

The arithmetic runs in your browser. This tool adds no input upload, saved record or input-bearing URL. Existing website consent, analytics and network services remain separate.