Board Foot Calculator

Multiply thickness (inches) × width (inches) × length (feet), then divide by 12: BF = T″ × W″ × L′ ÷ 12. For example, a 2″ thick × 8″ wide × 10 ft long board is 2 × 8 × 10 ÷ 12 = 13.33 board feet. This works because one board foot is defined as a 12″ × 12″ × 1″ block of wood (144 cubic inches), and the formula is just volume divided by 144. Enter your dimensions in the Single board tab and the calculator does it instantly — including a reverse solver that finds a missing dimension.

A board foot is the standard unit of volume for lumber in North America: one board foot equals a piece of wood 12 inches long × 12 inches wide × 1 inch thick, or any combination of dimensions with the same volume (144 cubic inches, 1/12 cubic foot, about 2,359,737 cubic mm). It is how hardwood is priced and sold at most lumberyards ($/BF), so converting your project into board feet is the first step to getting an honest price estimate.

Compute each board separately with BF = T × W × L ÷ 12, multiply by the quantity of identical boards, then add everything together. The Project tab on this page does exactly that: add one row per board size, enter the quantity, and it totals board feet, adds your waste allowance, and prices it per species. For example, two 1″×6″×8′ boards (8 BF) plus four 1.5″×3.5″×10′ boards (17.5 BF) total 25.5 board feet before waste.

Add 10% for straightforward projects from straight boards, 15–20% if you are cutting curves, short pieces, or matching grain, and 20–30% when buying rough-sawn or rough cut lumber that you will mill yourself (defects, checking, and surfacing eat more material). This calculator has waste presets from 0% to 50% plus common defaults — set it on the Project tab and the buy total updates live. It is cheaper to bring home one extra board than to stall a project for a lumberyard trip.

A nominal 2x4 is actually 1.5″ × 3.5″ — the name is the rough-sawn size before the lumber is dried and planed smooth (surfacing removes about 1/4″ per face). The Nominal tab has the full table: a 1x6 is really 0.75″ × 5.5″, a 2x8 is 1.5″ × 7.25″, a 4x4 is 3.5″ × 3.5″, and a 6x6 is 5.5″ × 5.5″. Always calculate board feet with the actual dimensions (a 2x4 × 10 ft board is 4.375 BF, not 6.67), and note that hardwood "quarters" work differently — see the next question.

Hardwood is sold in "quarters" of an inch of rough thickness: 4/4 (four-quarter) is 1″ thick rough, 5/4 is 1.25″, 6/4 is 1.5″, and 8/4 is 2″. Surfaced (S4S) boards are thinner — 4/4 dresses to 13/16″, 8/4 to 1-13/16″ — because planing removes material. The Quarters table in the Nominal tab lists rough and S4S thickness side by side, and board-foot math uses the rough (nominal) thickness you pay for.

Linear feet = board feet × 12 ÷ (thickness × width). For example, 10 board feet of 1″ × 8″ stock is 10 × 12 ÷ (1 × 8) = 15 linear feet of 1x8. This is handy when a lumberyard sells by the linear foot or you want to know how long your cut list will be. The reverse — linear feet to board feet — is simply BF = T × W × L ÷ 12 with the length in feet.

Square feet = board feet × 12 ÷ thickness. Ten board feet of 1″-thick stock covers 120 square feet (10 × 12 ÷ 1), but ten board feet of 2″ stock covers only 60 square feet. This matters for table tops, cutting boards, and flooring: the same board footage covers half the area at double the thickness. The Single board tab shows the square-footage equivalent of every calculation.

Enter or adjust the price per board foot for your species on the Species tab — 20 common species come with editable US retail defaults (poplar ~$4.50, red oak ~$6.50, black walnut ~$16.50, teak ~$28.00 per board foot) — and the Project tab multiplies each row by its species price to total the job. These defaults are starting points only: prices vary by region, grade, and lumberyard, so always edit them to match your local supplier before buying.

Measure the width at several points along the slab, average them (live edges taper), and use BF = thickness × average width × length ÷ 12. For example, a 2″ slab averaging 20″ wide and 8 ft long is 2 × 20 × 8 ÷ 12 = 26.67 board feet. The uneven-sides trick: because BF is just volume ÷ 144, an averaged width gives an honest answer — and add extra waste (20–30%) since you will lose more to flattening and bark removal than with straight boards.

Sheet goods are sold by the sheet or square foot, not by the board foot — but the math still works: a 3/4″-thick 4×8 sheet is 0.75 × 48 × 8 ÷ 12 = 24 board feet. In practice nobody prices plywood per board foot; use the result for cost comparisons only (e.g. comparing sheet stock vs. solid lumber). Note that this calculator targets solid lumber; plywood thickness is nominal and undersized (3/4″ plywood is typically ~0.70–0.72″).

Yes. Switch to metric and enter thickness and width in millimeters and length in meters — the math converts internally (1 board foot = 2,359,737.216 mm³, or 423.78 BF per cubic meter) and every result shows both systems. A 25.4 mm × 152.4 mm × 3.048 m board is exactly 5 board feet. Fractions work too: type 1-3/4 or 1 3/4 in any inch field.

One board foot = 0.002359737 cubic meters, and one cubic meter = 423.78 board feet. One board foot is also 1/12 of a cubic foot (144 cubic inches). The Single board tab shows every result in board feet, cubic feet, and cubic meters so you can quote your project in whatever unit your supplier uses.

It depends on the species and moisture content. As a rule of thumb at air-dry (~12% moisture), red oak runs about 3.7 lb per board foot, hard maple 3.7, black walnut 3.2, cherry 3.0, poplar 2.9, and western red cedar 1.9. The Species tab lists approximate weights per board foot for all 20 species, and the Project tab totals estimated lumber weight — useful for shipping quotes and trailer loads. Actual weight varies with moisture, so treat it as an estimate.

Surfacing removes real material: S2S (surfaced two sides) takes about 1/16″ off thickness (~6% BF loss on 4/4), and full S4S takes 3/16″ off thickness plus ~1/4″ off width (~21% BF loss on a 4/4 × 8″ board). The Project tab has milling presets that show your finished dimensions and the board-footage you will lose to the planer — buy rough lumber based on the gross board feet you need, not the finished size you want.

Yes. This board foot calculator runs 100% in your browser — every calculation happens on your device and nothing is sent to any server. There are no accounts, no tracking of your cut lists, and it keeps working offline after the first load.