Linear Feet Calculator
This linear feet calculator helps you convert a room’s square footage into linear feet of flooring, siding, or trim, or add up a cut list of individual piece lengths — with a waste allowance, board count, and material cost built in.
Also known as: linear footage calculator, LF calculator, linear ft calculator, board footage estimator, linear feet estimator.
Linear Feet = Area (sq ft) ÷ Board Width (ft)Step-by-step breakdown
- Enter values above to see the linear feet calculation unfold step by step.
Why Use a Linear Feet Calculator for Your Project
Ordering material by square footage alone often leads to the wrong quantity, because most flooring, decking, siding, and trim is priced and sold by the linear foot, not by the square foot. A linear feet calculator bridges that gap: it takes the area you need to cover, divides it by the actual width of the board or plank you plan to use, and returns the length of material to buy. In other words, this linear footage calculator turns a two-dimensional room measurement into a one-dimensional shopping number.
For projects that are not area-based at all — fencing, baseboard, crown molding, deck railing — the same tool works differently but just as usefully. Instead of dividing an area, it simply adds up every individual piece length multiplied by how many of that piece you need. This “list of pieces” mode is essentially a digital cut list, and it removes the guesswork that comes with manually tallying figures on paper or in a spreadsheet.
Because pricing for lumber, flooring, and trim is so frequently quoted per linear foot, having an accurate linear feet estimate also makes it far easier to compare supplier quotes side by side. Once you know the total, this calculator applies your price per linear foot automatically, so you get a materials-cost estimate in the same step as the quantity — no separate spreadsheet required.
How This Linear Feet Calculator Works
This linear feet calculator follows two straightforward paths depending on your project: converting an area into linear feet of material, or summing a cut list. Here is the logic behind each step.
Step 1 — area to linear feet
Multiply room length by room width to get the area in square feet. Then divide that area by the board’s width (converted to feet): Linear Feet = Area ÷ Board Width. A wider board covers the same area in fewer linear feet.
Step 2 — adding a waste allowance
Real installs lose material to cutting, pattern matching, and damaged pieces. This linear feet calculator applies your chosen waste percentage on top of the raw total, so the final figure reflects what you should actually order.
Step 3 — summing a cut list
For fencing, trim, or framing, total linear feet is simply the sum of every piece’s length times its quantity: Σ (Length × Quantity). No area calculation is needed for this mode.
Step 4 — boards and cost
Once total linear feet is known, dividing by a single board’s length gives the number of boards to buy, rounded up to a whole board. Multiplying total linear feet by your price per linear foot gives an estimated material cost.
Linear Feet Calculator: Worked Examples
Three common project types worked end-to-end using the same formulas as the calculator above.
Wide-plank flooring for a bedroom
A bedroom measures 12 ft by 10 ft, and you’re installing 5.5-inch wide-plank flooring sold in 8 ft boards with a 10% waste allowance. How many linear feet and boards are needed?
Given inputs
- Room: 12 ft × 10 ft
- Board width: 5.5 in
- Board length: 8 ft
- Waste allowance: 10%
Computed outputs
- Area: 120 sq ft
- Raw linear feet: 120 ÷ 0.458 ft ≈ 262 ft
- With 10% waste: ≈ 288 linear ft
- Boards needed: 288 ÷ 8 = 36 boards
Backyard fence perimeter
A backyard fence runs 40 ft along the back, 25 ft on each side, and 15 ft across the front (with a gate). What’s the total linear footage of fencing needed?
Given inputs (list of pieces)
- Back run: 40 ft × 1
- Side runs: 25 ft × 2
- Front run: 15 ft × 1
Computed outputs
- Sum: 40 + (25 × 2) + 15 = 105 linear ft
- Total fencing needed: 105 linear ft
- No area conversion is used — the “list of pieces” mode simply totals each run.
Baseboard trim cut list with cost estimate
A home needs baseboard trim: six 8 ft runs and three 7 ft runs, priced at $2.50 per linear foot. What’s the total linear footage and estimated cost?
Given inputs (list of pieces)
- Run A: 8 ft × 6
- Run B: 7 ft × 3
- Price: $2.50 / linear ft
Computed outputs
- Sum: (8 × 6) + (7 × 3) = 69 linear ft
- Total trim needed: 69 linear ft
- Estimated material cost: 69 × $2.50 = $172.50
Linear Feet Calculator Mistakes to Avoid
Confusing linear feet with square feet
Linear feet measures length only, with no regard for width. A 100-square-foot room can require very different amounts of linear footage depending on how wide the flooring or siding is — always convert through the board width, not the area alone.
Skipping the waste allowance
Cutting around corners, matching patterns, and replacing damaged pieces all consume extra material. Ordering the exact raw linear footage, with no buffer, is one of the most common reasons a project runs short mid-install.
Not rounding up to full boards
Suppliers sell whole boards, not fractional lengths. If your total comes out to 35.4 boards, you need 36 — always round the board count up, even when the decimal is small.
Ignoring layout direction on wide-plank or patterned material
Diagonal layouts, herringbone patterns, and wide-plank flooring typically consume more material per square foot than a straight run because of angled cuts. A higher waste percentage — often 15% or more — is appropriate for these layouts.
Assuming price per linear foot includes installation
Suppliers and contractors price materials and labor differently. A quoted price per linear foot may cover materials only — always confirm what is included before comparing quotes side by side.