Linear Feet Calculator

A linear feet calculator adds up length. A linear foot, also called a running foot or lineal foot, is 12 inches of material measured end to end, with no regard for how wide or thick the piece is. That makes it the natural unit for anything sold or installed by length: baseboard and casing, fencing, decking and flooring boards, gutters, edging and dimensional lumber priced per foot.

Three sister tools take the job further. The Board Feet Calculator measures lumber by volume, which is how hardwood is priced; the Deck Calculator builds a full decking, joist and footing list from a deck's length and width; and the Fence Calculator counts posts, rails and pickets. Use this page when the question is how many feet of material you need, or how linear feet relate to square feet and board feet.

What a linear foot measures

One linear foot is one foot of length: 12 inches, or exactly 0.3048 meter, the international foot that NIST defines for every U.S. measurement. A 16 ft 1x4 and a 16 ft 2x12 both contain 16 linear feet, even though the 2x12 holds six times as much wood. Width and thickness only matter when you convert linear feet into something else, either square feet of coverage or board feet of volume.

Lumber pricing leans on this unit. The uniform method-of-sale regulation in NIST Handbook 130, which states can adopt into law, requires a seller of softwood lumber to state the number of pieces, the actual or minimum dressed width and thickness, and "either the length of individual pieces or the lineal footage." Hardwood boards made to stock widths may likewise be sold by linear measure once their surfaced width and thickness are stated. A price per linear foot therefore always refers to one specific cross-section.

The formulas behind every mode

The factor 12 shows up everywhere because widths are measured in inches and lengths in feet. Dividing a width in inches by 12 turns it into feet, so a 5-1/2-inch board is 0.4583 ft wide and every linear foot of it covers 0.4583 sq ft. Turned around, it takes 12 ÷ 5.5 = 2.1818 linear feet of that board to cover one square foot.

Worked example: adding up a cut list

A trim carpenter's cut list for one room reads 6 pieces at 8 ft 0 in, 4 pieces at 12 ft 6 in and 3 pieces at 3 ft 4 in. Convert the inches first (6 in is 0.5 ft and 4 in is 0.3333 ft), then multiply and add:

• 6 × 8 ft = 48 LF
• 4 × 12.5 ft = 50 LF
• 3 × 3.3333 ft = 10 LF
• Total: 48 + 50 + 10 = 108 linear feet in 13 pieces

That is 1,296 inches, 36 yards or 32.92 meters. At $1.85 per linear foot the material costs 108 × $1.85 = $199.80. These are the default entries of the Add pieces mode above. The classic slip is typing 12 ft 6 in as 12.6 ft; it is 12.5 ft, and across four pieces that typo invents 0.4 ft of trim.

Worked example: square feet to linear feet for decking

A 200 sq ft deck surface will be covered with boards whose actual face is 5-1/2 inches, ordered in 16 ft lengths with a 10% allowance for cuts. Laid tight, the boards need 200 × 12 ÷ 5.5 = 436.36 linear feet. Adding 10% gives 480 LF, exactly 30 boards of 16 ft.

Real decking is spaced for drainage. With a 1/4-inch gap the effective width becomes 5.75 inches, so each linear foot covers more ground: 200 × 12 ÷ 5.75 = 417.39 LF, or 459.13 LF with waste, which rounds up to 29 boards (464 LF). The gap saved one board here; use the spacing your decking maker specifies. Flooring is the opposite case: tongue-and-groove strips butt tight, so enter a gap of zero and use the face width without the tongue.

Linear feet to square feet by board width

Converting between linear feet and square feet only needs the width the boards actually cover. Multiply linear feet by the third column to get square feet, or multiply square feet by the fourth column to get linear feet.

Nominal and actual sizes differ, and the difference matters here. The American Softwood Lumber Standard (PS 20-25) sets the minimum dry dressed width of a nominal 6-inch board at 5-1/2 inches and of a nominal 8-inch board at 7-1/4 inches, and NIST Handbook 130 describes a dry 2x4 as 1-1/2 by 3-1/2 inches. Handbook 130 figures the surface measure of hardwood boards the same way the table does, width in inches times length in feet divided by 12, before rounding to the nearest whole square foot. Using the nominal width for a 1x6 would overstate its coverage by about 9%.

Linear feet vs. board feet

A board foot is a unit of volume, not length. NIST Handbook 130 defines it as the volume of a board 1 ft long, 1 ft wide and 1 in thick, or 144 cubic inches, and the American Softwood Lumber Standard counts board feet from nominal dimensions: nominal thickness in inches times nominal width in feet times length in feet. Per linear foot that reduces to nominal thickness × nominal width ÷ 12.

So any question about board linear feet runs through the cross-section. A 2x6 holds exactly 1 board foot per linear foot, so 150 linear feet of 2x6 is 150 board feet. The same 150 linear feet of 1x6 is 75 board feet, and of 2x12 it is 300. Wholesale lumber is often quoted per thousand board feet; the last column turns 1,000 board feet back into running length for each size. Actual sizes in the second column are the dry dressed minimums from PS 20-25 Table 3 and do not enter the board-foot math.

Baseboard and trim for a room

Baseboard runs around the perimeter of a room and stops at every door opening. For a room 14 ft by 12 ft 6 in with two 36-inch openings, the perimeter is 2 × (14 + 12.5) = 53 ft and the openings take 2 × 3 = 6 ft, leaving 47 linear feet. With 10% for miters, copes and offcuts that becomes 51.7 LF: 4 pieces of 16 ft stock, or 7 pieces of 8 ft stock. Chair rail is figured the same way except that windows interrupt it too, while crown molding normally runs the full 53 ft.

The piece counts divide the footage with waste by the stock length and round up, so they assume offcuts can be reused on short walls. Longer stock means fewer joints: a 14 ft wall takes one 16 ft piece but needs a seam with 8 ft pieces. On a room with many short returns, add a piece.

Fence linear feet

A fence line is the sum of the sides you enclose. A back yard 60 ft wide and 80 ft deep, fenced along both sides and across the back with the house closing the fourth side, has a fence line of 80 + 80 + 60 = 220 linear feet. One 4 ft gate leaves 216 LF of fencing, exactly 27 panels of 8 ft. At an example installed price of $32 per linear foot, the fencing comes to 216 × $32 = $6,912 before the gate, which is normally priced as its own item.

Panel counts are a minimum, because each straight run needs whole panels: a 60 ft run takes 8 panels with one cut, not 7.5. For posts, rails and pickets, take the fence line to the Fence Calculator; for the boundary of a larger parcel, the Acreage Calculator reports the perimeter of rectangles, triangles, circles and irregular four-sided lots.

Cost per linear foot

To compare prices, bring every quote to a price per linear foot: price per piece ÷ piece length. For example, a 12 ft 2x6 priced at $11.88 costs $11.88 ÷ 12 = $0.99 per linear foot, and because a 2x6 holds 1 board foot per linear foot, that is also $0.99 per board foot. Buying 150 LF takes 13 pieces (156 LF) for $154.44. Those are the defaults of the Cost per foot mode.

The same division exposes length premiums. If an 8 ft board costs $7.28 ($0.91 per LF) and a 16 ft board of the same profile costs $15.68 ($0.98 per LF), the long board costs about 8% more per foot, worth paying only where it saves a joint. For hardwood priced by the board foot, multiply by the board feet per linear foot: 1x6 stock at an example $4.90 per board foot is $4.90 × 0.5 = $2.45 per linear foot.

How to use this linear feet calculator, and who it is for

1. Pick a mode: Add pieces, Sq ft ↔ linear ft, Trim & baseboard, Fence or Cost per foot. Each mode opens with one of the examples on this page.
2. Enter lengths in feet and inches. In Add pieces, each row is a group of identical pieces; add rows for other lengths.
3. For coverage, enter the actual face width and any gap, or tap one of the dressed-width chips.
4. Add a waste allowance and a stock length to turn the exact footage into whole pieces to buy.
5. Add a price per linear foot to see the material cost, or switch to Cost per foot to work out the price from a tag.

Remodelers ordering baseboard, casing and crown use the trim mode to turn room sizes into stock lengths. Deck builders and flooring installers translate square footage into boards. Homeowners comparing fence quotes check that every bid covers the same footage before comparing prices per foot. Estimators use the cut-list mode for takeoffs, and lumber yard customers use the cost mode to compare a price per piece, a price per linear foot and a price per board foot on equal terms.

Key terms

• Linear foot (LF, lin ft): 12 inches of length, also called a lineal or running foot.
• Board foot (bd ft): 144 cubic inches of wood, counted from nominal size.
• Nominal size: the name of a board, such as 2x6. It is always larger than the actual dressed size.
• Face width: the width that shows once installed; for tongue-and-groove stock it excludes the tongue.
• Exposure: the part of a lap siding board left visible below the course above it; it sets the coverage.
• Stock length: the length a product is sold in, such as 8, 12 or 16 ft.
• Waste allowance: extra length for cuts, defects and mistakes, usually 5% to 15%.

What changes the result, ordering tips and limitations

• The width you use: actual face width instead of nominal changes coverage by about 9% for a 1x6.
• Gaps: spaced decking needs fewer linear feet per square foot than tight flooring.
• Pattern: diagonal and herringbone layouts cut more material, so raise the waste allowance.
• Stock length: it changes the number of pieces and joints, not the linear footage.
• Openings: doors come out of baseboard, windows come out of chair rail, and gates come out of fencing.
• Tip: buy trim from one production run if you can; profiles and colors drift between batches, so a small extra now beats a mismatched piece later.

The calculator measures straight lengths and does not lay out individual boards, stagger joints or plan miter angles, so the waste allowance carries those costs. Fence mode assumes a rectangle and counts panels, not posts, footings or rails. Coverage figures assume a uniform width and a flat surface. Prices are whatever you enter, and lumber prices move, so check the current tag before you buy.

Related calculators

• For lumber volume and hardwood pricing, use the Board Feet Calculator.
• For a full deck materials list, use the Deck Calculator.
• For posts, rails and pickets, use the Fence Calculator.
• For flooring boxes and square footage, use the Flooring Calculator.
• For the perimeter of other shapes, use the Perimeter Calculator, and for room areas the Square Footage Calculator.

Sources

• National Institute of Standards and Technology (NIST), Voluntary Product Standard PS 20-25, American Softwood Lumber Standard (January 2025): board measure from nominal thickness, width and length; Table 3 minimum dressed sizes.
• NIST Handbook 130 (2026), Uniform Regulation for the Method of Sale of Commodities: section 2.10 (softwood lumber sold by piece length or lineal footage; a dry 2x4 is 1-1/2 × 3-1/2 in) and section 2.12 (board foot = 144 cubic inches; surface measure; linear measure).
• NIST, U.S. Survey Foot: 1 foot = 0.3048 meter exactly.