Linear Feet Calculator

What Linear Feet Means

Linear feet (sometimes called running feet) measure length in one dimension. One linear foot equals 12 inches. The key word is “linear”: it is a straight-line measurement used for anything you buy, build, or install by length. Examples include baseboard, crown molding, trim, fencing, edging, piping, lumber lengths, and many construction materials sold per foot.

People often confuse linear feet with square feet. Square feet are an area measurement (length × width). Linear feet do not include width. That difference matters when you are buying materials. A 10-foot board is 10 linear feet, regardless of whether it is 2 inches wide or 12 inches wide. But if you are estimating coverage (like flooring planks or carpet roll), you need both the linear length and the width to calculate area.

The Simple Linear Feet Formula

In most projects, calculating linear feet is just addition. If you have several runs, you add each run’s length to get a total. The only tricky part is unit consistency. If one wall is measured in feet and another is measured in inches, convert one so everything is in the same unit, then add.

This calculator totals multiple runs and handles common unit conversions automatically. If your measurements are in inches, the calculator converts inches to feet by dividing by 12. If you measure in meters or centimeters, the calculator converts to feet using standard conversion factors and still reports totals in multiple units so you can verify the result.

Where Linear Feet Is Used Most

Linear feet is a common pricing and planning unit because it maps directly to real installation work. Contractors often estimate labor and materials per linear foot for trim installs, fence lines, edging, and many site features. Homeowners and DIY builders use linear feet to avoid under-buying materials.

• Baseboard and trim: Total wall lengths minus openings.
• Fencing: Perimeter of the yard or boundary line.
• Deck boards: Boards count × board length.
• Piping: Total run length including rises and drops.
• Edging and borders: Garden beds, driveways, and paths.

Linear Feet vs Square Feet

If you are buying something sold by length but you want to understand how much area it covers, you must include width. The relationship is:

Area = Length × Width

If your length is in feet and width is in feet, the area is in square feet. If width is in inches, convert inches to feet first. For example, 100 linear feet of a 6-inch-wide roll is 100 × (6 ÷ 12) = 50 square feet, before waste.

The Linear to Area tab does this conversion for you and also lets you add a waste percentage. Waste is realistic because cuts, seams, and layout constraints mean you rarely use every inch of material efficiently.

Estimating Trim for Rooms

Trim estimation often starts with perimeter, but rooms are not always perfect rectangles. A more reliable approach is to add each wall length and subtract openings you do not trim, like doorways. This calculator includes a Room Trim mode so you can enter wall lengths directly and subtract openings as one total.

Many installers also add a small buffer for corners and seams, especially when trim comes in fixed lengths. Corner cuts, miter mistakes, and slightly out-of-square rooms can cause small waste. A corner buffer is not a substitute for a proper waste percentage, but it helps avoid coming up short on finishing pieces.

Boards, Pieces, and Cut Loss

Materials are often sold as pieces: 8-foot boards, 10-foot trim sticks, or pipe segments. In that case, linear feet is calculated by multiplying the number of pieces by the length of each piece.

Real projects include cut loss. If you are cutting many small segments from long pieces, offcuts and kerf (the width of the saw blade) add up. The Boards & Pieces tab lets you include a cut-loss percentage so your linear feet estimate reflects real conditions rather than ideal math.

How Much Waste Should You Add?

Waste depends on material type and layout complexity. Straight installs with few cuts might only need 5%. Rooms with many corners, angles, or mistakes during cutting can require 10–15%. Fragile materials or projects where matching grain and pattern matters can require more.

A good practical approach is to use the calculator in scenarios. Run the numbers at 5%, 10%, and 15% waste and compare costs. If the cost difference is small, choosing the safer waste percentage helps prevent last-minute shortages.

Cost per Linear Foot

Pricing by linear foot is common for materials and sometimes for labor. If your vendor quotes a price per foot and you know your total linear feet, total material cost is:

Total cost = (Linear feet × Price per linear foot) + Fixed fees

The Cost & Waste tab converts your input length into feet, applies waste, multiplies by your price per linear foot, and adds any fixed fee. This makes it easy to compare options like a lower per-foot price with a higher delivery fee versus a higher per-foot price with no fee.

Common Mistakes and Quick Checks

• Forgetting unit conversion: inches must be converted to feet before you add to feet values.
• Using linear feet for area without width: you need width to get square feet.
• Not subtracting openings for trim: doors and large gaps reduce total trim needed.
• Ignoring waste: cuts, corners, and mistakes are normal; add a buffer.
• Assuming all rooms are rectangles: enter wall lengths directly if the room is irregular.

How to Use This Calculator Fast

If you already have a list of measured segments, use Total Linear Feet (Multiple runs) and enter each length as a row. If you are measuring a fence or border around a rectangle, use Rectangle perimeter. If you are estimating trim in a room, use Room trim and subtract openings.

Then, if you need coverage, switch to Linear to Area and enter the width of the material. If you are buying boards by piece count, use Boards & Pieces. Finally, use Cost & Waste to estimate total spend using your vendor’s rate per linear foot.