Calculate linear feet for trim, lumber, fencing, or molding. Enter the total length, pick a stock piece length, and add waste to get the pieces and linear feet to buy.
Usage Tip
Choosing a stock length that divides evenly into your runs cuts waste. Longer pieces mean fewer seams but are harder to handle and transport.
With waste = length × (1 + waste%)
Pieces = round up (length with waste ÷ stock length)
Stock lumber and trim commonly come in 8, 10, 12, and 16 ft lengths.
Add waste for miter cuts, end trimming, and mistakes; 10% is a common start, more for many short pieces or angled cuts.
For trim around a room, measure each wall and subtract door and window openings the trim does not cross.
What Is a Linear Foot?
A linear foot is simply one foot of length measured in a straight line – nothing more. It ignores width and thickness entirely. If you lay a tape measure along a wall, a fence line, or a row of trim and read 24 feet, that is 24 linear feet. Material sold by the linear foot (trim, molding, fencing, pipe, decking, fabric) is priced by how much length you need, not area.
Linear Feet vs Square Feet (read this first)
This is the distinction people get wrong constantly, so here it is plainly: a linear foot measures length only (one dimension). A square foot measures area – length times width (two dimensions). They are not interchangeable and you cannot convert between them without knowing the width.
| Linear foot | Square foot | |
|---|---|---|
| Measures | Length only (1D) | Area: length x width (2D) |
| Use it for | Trim, molding, baseboard, fence, pipe, decking, fabric | Flooring, paint, tile, drywall, sod |
| Example | 40 ft of baseboard | 200 sq ft of floor |
How to Measure Linear Feet
Measure each straight run and add them up. For anything that goes around a room (baseboard, crown molding), measure the perimeter and subtract door openings. The calculator above lets you enter each wall or section on its own line and totals them for you.
| Project | What to measure |
|---|---|
| Baseboard | Wall perimeter (minus doorways) |
| Crown molding | Ceiling perimeter |
| Fence | Total fence run length |
| Deck boards | Total length of all boards (or area divided by board width) |
| Shelving | Sum of all shelf lengths |
| Pipe / conduit | Sum of all runs, plus extra for bends |
Trim, Molding & Baseboard Guide
For baseboard or crown, walk the room and measure each wall. Add them for the perimeter, then subtract the width of door openings (but keep window trim if you are casing windows). Baseboard example: a 12 x 14 ft room has a 52 ft perimeter; minus a 3 ft doorway leaves 49 linear feet. With 10% waste that is about 54 ft, or five 12 ft sticks. Always round up to whole sticks – trim is sold in fixed lengths.
Fencing Linear Feet Guide
Fencing is quoted per linear foot of run. Measure the total length of the fence line (not the area it encloses). Fence example: a yard needing 60 + 40 + 60 ft of run is 160 linear feet. Rails and pickets are figured from that run; posts are spaced along it (commonly every 8 ft, so about 21 posts here). Add a little waste for cuts at corners and gates.
Deck Board Linear Feet Guide
Decking is often bought by the linear foot. Two ways to get the number: sum the length of every board row, or take the deck area and divide by the coverage width of one board (a 5.5 in board covers about 0.46 ft, so 200 sq ft needs roughly 200 / 0.46 = 435 linear feet). Add 10 to 15% for cuts, waste, and pattern. The calculator handles the waste and board-length math for you.
Linear Feet to Boards Chart
How many sticks you buy depends on the length they come in. Pieces needed (rounded up, before waste):
| Linear feet needed | 8 ft boards | 12 ft boards | 16 ft boards |
|---|---|---|---|
| 20 ft | 3 | 2 | 2 |
| 40 ft | 5 | 4 | 3 |
| 60 ft | 8 | 5 | 4 |
| 100 ft | 13 | 9 | 7 |
Trim Waste & Buying Tips
- Add 10% waste for straight runs, 15% for lots of corners or angled cuts.
- Buy whole sticks in the longest length that fits your vehicle – fewer joints, less waste.
- Keep offcuts for short sections rather than opening a new piece.
- Inside corners are coped or mitered; outside corners are mitered – both eat a little length.
- Order one extra stick for mistakes; returning one is easier than a second trip.
Common Measuring Mistakes
- Confusing linear feet (length) with square feet (area).
- Forgetting to subtract door openings on baseboard.
- Measuring the area a fence encloses instead of the run length.
- Skipping waste, then coming up one stick short.
- Ignoring that boards come in fixed lengths – you buy whole sticks.
Frequently Asked Questions
What is a linear foot?
One foot of length measured in a straight line, regardless of width or thickness. Add up your runs to get total linear feet.
What is the difference between linear feet and square feet?
Linear feet measure length only; square feet measure area (length times width). Use linear feet for trim, fencing, and pipe; square feet for flooring and paint.
How do I calculate linear feet?
Measure each straight section and add them together. For a room perimeter, add all wall lengths and subtract door openings.
How many boards do I need for a given linear footage?
Divide the waste-adjusted linear feet by the board length and round up. For 54 ft with 12 ft boards, that is five boards.
Should I add waste?
Yes – about 10% for straight runs and 15% for projects with many corners or angled cuts.
How do I measure baseboard in linear feet?
Measure the perimeter of the room (add every wall) and subtract the width of doorways. That total is your baseboard linear footage.
Related Measuring & Layout Calculators
Note: linear feet measure length only – not area or volume. Results are rounded for display. Add a waste allowance for cuts, corners, and mistakes, and remember material is sold in fixed lengths, so round up to whole pieces. Measurements vary in the field; confirm your own before buying. General DIY guidance, not a professional estimate.