Board Feet vs Linear Feet Explained

Lumber gets priced in two different units, and mixing them up costs real money. A linear foot measures length only. A board foot measures volume, so it counts thickness and width too. Knowing which unit a price tag uses tells you exactly what you are paying for, and it keeps your material estimate honest before you order a single board.

What Is a Linear Foot?

A linear foot is 12 inches of length measured along a single line. Width and thickness do not matter. A 2×4 that is 8 feet long measures 8 linear feet, and so does a 1×12 that is 8 feet long, even though the 1×12 holds far more wood.

Linear feet suit products sold in long, uniform shapes. Baseboard, crown molding, fence rails, pipe and wire all sell this way. Every piece has the same profile, so length alone sets the price.

A linear foot is not a square foot. A square foot measures area, which is length times width. A linear foot measures one dimension only. Mixing the two is a common estimating mistake, and it leads to ordering the wrong amount of material.

To find linear feet, add up the length of every piece. Ten boards at 8 feet each make 80 linear feet. A wall run of 24 feet needs 24 linear feet of baseboard before any extra for cuts. Reading those lengths off a drawing is covered in our guide on how to read construction measurements and blueprints.

What Is a Board Foot?

A board foot is a unit of wood volume equal to 144 cubic inches. That matches a board 1 inch thick, 12 inches wide and 12 inches long. Sawmills and hardwood dealers use it because it counts thickness, width and length together.

Check the number yourself. Multiply 1 x 12 x 12 and you get 144 cubic inches. One cubic foot is 12 x 12 x 12, which equals 1,728 cubic inches. Divide 1,728 by 144 and you get 12, so one cubic foot of lumber holds exactly 12 board feet.

The unit rewards thickness. A plank 2 inches thick holds twice the wood of a board 1 inch thick with the same width and length, and it carries twice the board feet. Length alone hides that difference, which is why hardwood dealers avoid pricing by the linear foot.

Rough hardwood often arrives labeled in quarters of an inch. A label of 4/4 means 1 inch thick, 5/4 means 1.25 inches, and 8/4 means 2 inches. Dealers then price each board by the board foot at that thickness.

How Do You Calculate Board Feet?

Multiply thickness in inches by width in inches by length in feet, then divide by 12. The formula reads: board feet = thickness x width x length / 12. The 12 converts the length from feet into inches so the total matches the 144 cubic inch definition.

Here is a first example. A board is 2 inches thick, 6 inches wide and 8 feet long. Multiply 2 x 6 to get 12. Multiply 12 x 8 to get 96. Divide 96 by 12 to get 8 board feet.

Here is a second example. A board is 1 inch thick, 8 inches wide and 10 feet long. Multiply 1 x 8 to get 8. Multiply 8 x 10 to get 80. Divide 80 by 12 to get 6.67 board feet, rounded to two decimals.

Length in inches works too, with one change. Divide by 144 instead of 12. The same 1 x 8 board is 120 inches long, so 1 x 8 x 120 = 960, and 960 / 144 = 6.67 board feet. Both routes agree.

For many pieces, find one board and multiply by the count. Twelve boards of 1 x 6 x 8 feet hold 4 board feet each, so the order totals 12 x 4 = 48 board feet. The table below shows common sizes at 8 feet, using the nominal size described in the next section.

Every row has the same 8 linear feet, yet the board feet range from 2.67 to 16.00. That spread is the whole reason the two units exist side by side.

Why Do Nominal and Actual Lumber Sizes Matter?

Nominal size is the name of a board, and actual size is what you can measure with a tape. A 2×4 is named 2 inches by 4 inches, but it measures 1.5 inches by 3.5 inches. Mills cut boards to the named size while the wood is wet, then drying and planing shrink them.

The gap changes your numbers. Dimensional lumber sold by the board foot usually uses the nominal size in the math, so the yard bills you for 5.33 board feet on a 2×4 that is 8 feet long. The actual volume is 1.5 x 3.5 x 96 = 504 cubic inches, and 504 / 144 = 3.5 board feet. The board holds about 66 percent of the wood its name suggests.

Hardwood follows a different habit. Dealers measure rough hardwood at its rough thickness, before planing, and price it from that figure. Ask the seller which size their math uses before you compare quotes.

MultiCalculators has no lumber calculator, but a board foot is a unit of volume, so the Volume Calculator handles the underlying thickness x width x length math. Enter 1.5 x 3.5 x 96 inches for the actual 2×4 and divide the answer by 144 to get board feet.

How Do Prices Compare Per Board Foot and Per Linear Foot?

Per-board-foot pricing scales with wood volume, while per-linear-foot pricing scales with length for one fixed size. Both work, but only the board foot price lets you compare boards of different sizes fairly. The prices below are illustrative examples, since real prices vary by species, region and season.

Take oak at $8.00 per board foot. A 1×4 holds 1 x 4 / 12 = 0.33 board feet per linear foot, so it costs $2.67 per linear foot. A 1×8 holds 0.67 board feet per foot and costs $5.33. A 1×12 holds 1 board foot per foot and costs $8.00.

Now price a full 10-foot board of each width. The table shows the same $8.00 rate applied to board feet, then the total.

Each row has 10 linear feet, yet the totals differ threefold from the 1×4 to the 1×12 board. A quote of “$5.33 per foot” therefore means nothing until you know the board width.

Dimensional lumber shows the opposite trap. A 2×4 stud, 8 feet long, sells for $4.00 in this example. That is $0.50 per linear foot and $0.75 per board foot on the nominal 5.33 board feet. A 2×6 that is 8 feet long sells for $6.00, or $0.75 per linear foot and also $0.75 per board foot on 8 nominal board feet. The per-foot prices differ, but the board foot prices match, which tells you neither board is a bargain over the other.

Compare that to the oak at $8.00. Oak costs more than ten times as much per board foot as the studs at $0.75. Carry the resulting cost into your line items, as shown in our guide on how to estimate a renovation budget.

Which Unit Should You Use for Your Project?

Use board feet to compare or buy wood by volume, and use linear feet to count runs of one fixed size. Board feet suit hardwood, furniture stock, shelving and any job mixing several board sizes. Linear feet suit trim, framing, fencing and decking, where every piece shares one profile.

Decking is the classic linear foot job. Count the rows across the deck, multiply by the length of each row, and add the totals. Our deck board spacing and quantity guide walks through that count.

A short routine keeps a board foot order accurate. List every piece with its thickness, width and length. Convert each line to board feet with the formula. Add the lines together, then add a waste allowance. A 10 percent allowance on 48 board feet gives 48 x 1.10 = 52.8, so you round up and order 53 board feet. The method for choosing that allowance appears in our article on how to calculate material waste and overage.

Three mistakes cause most errors. Some people multiply thickness and width in inches but leave length in feet without dividing by 12. Others mix nominal and actual sizes in one calculation. The third mistake is comparing a per-linear-foot price against a per-board-foot price as if the units matched.

FAQs About Board Feet and Linear Feet

Sources

This article is general education, not professional construction, engineering or contracting advice. Local building codes, material sizes and prices vary, so confirm details with a licensed professional and your local code office. Reviewed for accuracy by Prof. Dr. Khalil Mudassar, PhD. Last updated September 22, 2026.