Linear Foot Calculator (Square Feet to Linear Feet)
Here's the thing most conversion pages skip: you can't turn square feet into linear feet without knowing how wide your material is. Square feet measure area. Linear feet measure length, and nothing else. The width of your planks, boards, or fabric is what ties the two together. Give this converter your area and your material width, and it does the rest.
What is a linear foot?
A linear foot is one foot of length along a straight line, with no width attached. That's the whole definition. It's also written as a lineal foot, and the two mean the same thing.
A square foot is different: it measures area, a patch of surface one foot by one foot. When a lumberyard sells trim at $2 per linear foot, the price doesn't care whether the trim is half an inch wide or four inches wide. You're paying for length.
Materials sold by the linear foot are the ones where width is fixed by the product: trim, baseboard, crown molding, dimensional lumber, decking, countertop runs, fencing, gutters, fabric off a bolt, and cabinets. Decking is the clearest everyday case, and the deck calculator runs it both ways at once. Materials sold by the square foot are the ones that cover a surface: flooring, tile, carpet, drywall, and sod.
That's why "how many linear feet is 200 square feet" has no single answer until you add one more number. A 200 square foot floor might take 480 linear feet of 5 inch planks, or 400 linear feet of 6 inch planks, or 800 linear feet of 3 inch strip flooring. The area is identical. The length you buy changes with the width.
The formula
To go from area to length:
Linear feet = square feet ÷ width in feet
The only trap is the width. Most flooring, trim, and lumber widths are given in inches, so convert to feet first by dividing by 12. A 5 inch plank is 5 ÷ 12 = 0.4167 feet wide. A 6 inch board is 6 ÷ 12 = 0.5 feet.
To run it the other direction (linear feet to square feet), just multiply:
Square feet = linear feet × width in feet
That second version is the linear feet to square foot calculator people search for when they already know how many feet of board they have and want to know the coverage.
How to calculate linear feet
For a material that covers an area, work from the square footage:
- Measure the area you're covering and get the square footage (length times width).
- Measure the material's face width in inches. Use the actual width, not the nominal name.
- Divide that width by 12 to get feet.
- Divide the square footage by the width in feet.
- Add the waste factor on the linear figure, not the area figure.
For trim, fencing, gutters, or countertop, there's no area step at all. You're measuring length directly:
- Measure each run in feet along the wall, the fence line, or the cabinet.
- Add the runs together.
- Subtract door openings for baseboard, and add 10 percent for miter cuts and offcuts.
That second case is what people mean by measuring linear feet: it's a tape along the wall, and the answer is already in linear feet without any conversion.
Board feet vs linear feet
These get mixed up constantly at the lumberyard and they measure different things.
A linear foot is length only. A board foot is a volume: 144 cubic inches, equal to a piece 12 inches wide, 12 inches long, and 1 inch thick. So a 10 foot 1x6 board is 10 linear feet but 5 board feet, because a nominal 1x6 measures about 5.5 inches wide and 0.75 inches thick.
Rough lumber and hardwood are usually priced by the board foot. Trim, molding, and dimensional softwood are usually priced by the linear foot. If a quote looks strangely cheap or expensive, check which unit it's in.
Worked example 1: 200 sq ft of 5 inch hardwood planks
Say you're flooring a room that measures out to 200 square feet, and you've picked a hardwood plank that's 5 inches wide.
- Convert the width to feet: 5 ÷ 12 = 0.4167 ft.
- Divide the area by that width: 200 ÷ 0.4167 = 480 linear feet.
So you need 480 linear feet of plank to cover 200 square feet, before waste. Nobody installs flooring with zero waste, though. Cuts at the walls, bad boards, and the last row rarely landing clean all eat material. Add 10 percent and you're buying 528 linear feet. For hand cut or reclaimed stock where more pieces get rejected, bump the waste factor to 15 or 20 percent.
If the boxes at the store list coverage in square feet instead of linear feet, you don't even need this step for the purchase itself. But knowing the linear footage still helps when you're pricing trim, quarter round, or transition strips that sell by the foot.
Worked example 2: lumber boards for a deck surface
You're decking over a 320 square foot platform with 5.5 inch wide boards. A board sold as a "1x6" or "5/4x6" is not actually 6 inches wide once it's milled; the real face width is 5.5 inches, per standard dimensional lumber sizing (Lowe's spells this out). Use the real number, not the name.
- Convert the width to feet: 5.5 ÷ 12 = 0.4583 ft.
- Divide the area by that width: 320 ÷ 0.4583 = 698 linear feet.
That 698 figure assumes the boards butt together with no gap. Deck boards usually get an eighth inch gap for drainage and expansion, which slightly reduces how many linear feet you need, but the difference is small and waste from cuts more than covers it. Add 10 to 15 percent for end cuts and the odd cracked board, so plan on about 780 to 800 linear feet. If you're figuring the surface area first, the how to calculate square footage guide handles the measuring.
Worked example 3: trim and baseboard
Trim is the one case where you usually skip the square footage entirely. Baseboard, crown, quarter round, and casing run along edges, so you measure length directly, not area. For a 12 by 14 room, the perimeter is 2 × (12 + 14) = 52 linear feet. Subtract the door openings (say two 3 foot doors, so 6 feet) and you're at 46 linear feet of baseboard, plus 10 percent for miter cuts and mistakes, which rounds to about 51 feet.
Baseboard and crown have enough of their own arithmetic to be worth a dedicated tool: the baseboard and trim calculator takes the room dimensions, subtracts the openings, and then works out how many whole sticks to buy, which is a different calculation from the linear footage and usually a larger number.
The reason people still land on this converter for trim is that they're pricing a wainscot or a plank accent wall where the material comes in strips of a known width and they know the wall's square footage. In that case the formula applies exactly as it does for flooring: wall area divided by strip width in feet gives the running length.
Worked example 4: fabric off a bolt
Fabric, wallpaper, and vinyl come off a roll at a fixed width, so the same math converts the area you need into running length (yardage). Quilting cotton is commonly 44 to 45 inches wide, while home decor and upholstery fabric is often 54 inches wide (standard bolt widths here).
Say you need to cover 30 square feet with 54 inch fabric.
- Convert the width to feet: 54 ÷ 12 = 4.5 ft.
- Divide the area by that width: 30 ÷ 4.5 = 6.67 linear feet.
That's 6.67 feet along the bolt, or 2.22 linear yards. Fabric almost always needs extra for pattern repeats and matching seams, so round up generously, often to the next half yard or full yard depending on the print.
Linear yards, and the factor-of-four trap
Fabric and broadloom carpet are not sold by the linear foot. They are sold by the linear yard, which is simply three linear feet off the same fixed-width roll. So the conversion gains one division:
Linear yards = square feet ÷ width in feet ÷ 3
What each linear yard actually gets you depends entirely on the roll width:
| Material | Roll width | One linear yard covers |
|---|---|---|
| Quilting cotton | 45 in (3.75 ft) | 11.25 sq ft |
| Upholstery and home decor | 54 in (4.5 ft) | 13.5 sq ft |
| Broadloom carpet | 12 ft | 36 sq ft |
| Wide broadloom | 15 ft | 45 sq ft |
Now the trap, and it is an expensive one. A linear yard and a square yard are different units, and on standard 12 foot broadloom they are four times apart. One linear yard of a 12 foot roll is 36 square feet, and 36 square feet is 4 square yards. So if a supplier quotes in linear yards and you order thinking in square yards, you are out by a factor of four in whichever direction hurts.
Carpet makes this worse by having switched conventions. US retail moved to pricing carpet by the square foot years ago, but the mills still roll and bill broadloom by the linear yard, so the two units sit side by side in the same transaction. Ask which one a number is in before you agree to it. The square feet to square yards converter handles the area side.
Worked example. A 300 square foot room in 12 foot broadloom: 300 ÷ 12 = 25 linear feet, ÷ 3 = 8.33 linear yards. In a 15 foot roll it is 300 ÷ 15 ÷ 3 = 6.67 linear yards. Round up to whole or half yards, and add waste on top, because a fixed-width roll almost never matches your room and the offcut down one side is yours whether you use it or not.
Quick reference: coverage per linear foot
Each linear foot of material covers width-in-feet worth of square footage. Here's what common widths give you, including how many linear feet you need for 100, 200, and 500 square feet.
| Material width | Sq ft per linear foot | Linear ft for 100 sq ft | Linear ft for 200 sq ft | Linear ft for 500 sq ft |
|---|---|---|---|---|
| 2.25 in | 0.188 | 533 | 1,066 | 2,665 |
| 3 in | 0.250 | 400 | 800 | 2,000 |
| 3.25 in | 0.271 | 369 | 738 | 1,845 |
| 4 in | 0.333 | 300 | 600 | 1,500 |
| 5 in | 0.417 | 240 | 480 | 1,200 |
| 6 in | 0.500 | 200 | 400 | 1,000 |
| 7.5 in | 0.625 | 160 | 320 | 800 |
| 12 in | 1.000 | 100 | 200 | 500 |
Scale it to any job. For 250 square feet of 5 inch plank, take the 240 figure for 100 sq ft and multiply by 2.5, which gives 600 linear feet. That matches what folks work out in a long TractorByNet forum thread on square feet to linear foot conversion, where the running advice is simple: a 5 inch board covers about 0.415 square feet per foot, so 600 linear feet gets you 250 square feet, then add waste on top.
Running it in reverse: linear feet to square feet
Plenty of people land here with the opposite problem. They've got a stack of board and want to know how much floor or wall it covers. Multiply instead of divide.
Say you bought 350 linear feet of 3.25 inch flooring and want the coverage. Width in feet is 3.25 ÷ 12 = 0.271. Multiply: 350 × 0.271 = 94.9 square feet. So that bundle covers a hair under 95 square feet before waste, meaning the actual installed coverage is a bit less once cuts are subtracted. This is the reverse case the "linear feet to square foot calculator" searches are really asking for.
Why waste still applies either direction
The formula gives a theoretical minimum, the length you'd need if every board went down whole with zero offcuts. That never happens. When you convert square feet to linear feet, add waste on top of the result before you buy. When you convert linear feet to square feet, remember your real coverage is lower than the raw number because cut ends and rejected pieces don't make it onto the floor.
Ten percent is the common starting point for a plain rectangular room. Diagonal or herringbone layouts waste more because every board meets a wall at an angle, so plan 15 percent or more. Reclaimed and character grade material can lose 20 percent to defects. Skipping the waste factor is the fastest way to end up one row short with the store out of your dye lot.
Common mistakes
Forgetting the width entirely. The number one error. There's no fixed conversion from square feet to linear feet. Anyone who gives you one without asking your material width is guessing.
Leaving the width in inches. If you plug 5 into the formula instead of 0.4167, your answer is off by a factor of 12. Convert inches to feet first, or use a converter that does it for you.
Ignoring waste. The raw number is the floor, not the order. Cuts, defects, and pattern matching mean you buy more than the theoretical minimum.
Confusing face width with nominal size. A board sold as a "1x6" is 5.5 inches wide, not 6. Nominal lumber shrinks below its name once it's milled. Measure the actual face width, or check the spec sheet.
Frequently asked questions
What is a linear foot?
One foot of length along a straight line, with no width involved. It's the unit used for trim, lumber, fencing, countertop, and fabric, where the width of the product is already fixed. A lineal foot is the same thing.
How do I measure linear feet?
Run a tape along the wall, fence line, or cabinet run and add the sections together. That total is already in linear feet. You only need a conversion when you're starting from an area in square feet and a material width.
How do I convert square feet to linear feet?
Divide the area in square feet by the material's width in feet. Convert the width from inches to feet first by dividing by 12. For example, 200 square feet of 6 inch material is 200 ÷ 0.5 = 400 linear feet.
Can I convert square feet to linear feet without knowing the width?
No. Square feet measure area and linear feet measure length, so the width is the missing link between them. Two materials with the same square footage will need different linear footage if their widths differ.
How do I use a linear feet to square feet calculator the other way?
Multiply the linear feet by the width in feet. If you have 400 linear feet of 6 inch board, that's 400 × 0.5 = 200 square feet of coverage.
How much waste should I add when converting for flooring?
For a standard rectangular room, 10 percent is a reasonable starting point. Add 15 percent for diagonal layouts or busy patterns, and up to 20 percent for reclaimed or hand cut material where more pieces get rejected.
What's the difference between linear feet and board feet?
Linear feet measure length only. Board feet measure volume and factor in thickness as well as width and length. Trim and flooring are usually sold by the linear foot, while rough lumber is often priced by the board foot.
How many linear feet are in a square foot?
It depends entirely on width. At a 12 inch width, one square foot equals one linear foot. At a 6 inch width, one square foot takes 2 linear feet. Narrower material means more linear feet per square foot.
How wide is a bolt of fabric for converting yardage?
Quilting cotton is usually 44 to 45 inches wide, and home decor or upholstery fabric is commonly 54 inches. Divide the square footage you need by the width in feet to get the running length, then convert to yards by dividing by 3.
Why is my "1x4" board not 4 inches wide?
Nominal lumber names refer to the rough size before milling and drying. A 1x4 finishes at about 3.5 inches wide and a 1x6 at 5.5 inches. Always use the actual face width in the conversion.
For any other shape or a whole project at once, start from the main square footage calculator.
Sources
- Nominal vs actual lumber sizes, Lowe's
- Fabric bolt widths explained, The Fabric Calculator
- Square feet to linear foot conversion thread, TractorByNet forums
Related tools: flooring calculator, wall calculator, and the how to calculate square footage guide.