Measurement
Linear Feet Calculator
Use this linear feet calculator to add up lengths of trim, baseboard, fencing, gutter or lumber, or to convert square feet to linear feet when you know the material width. Enter a stock length to see how many pieces to buy and add a price to estimate the cost.
Result
Enter your measurements and press Calculate. What to buy, the working and the cost will appear here.
What is a linear foot?
A linear foot is simply one foot of length, measured in a straight line, whatever the width or thickness of the material. Ten linear feet of 1×4 trim and ten linear feet of 2×12 joist are both 10 ft long. That makes linear feet the natural unit for anything sold by length: trim, baseboard, crown molding, fencing, gutters, pipe, edging and dimensional lumber.
How to use the linear feet calculator
- Choose what you know. Pick The lengths to cover to add up runs such as walls or fence sides, or An area and the material width to convert square feet to linear feet.
- Enter the lengths (use How many for repeats) or the area and the width of each board.
- Add a stock length (optional), such as 8, 12 or 16 ft, to see how many pieces to buy.
- Set the allowance for mistakes and end trimming; 10% is a common starting point for trim.
- Add a price per foot or per piece to estimate the cost, then press Calculate.
Linear feet formulas
Adding lengths
linear feet = length 1 + length 2 + length 3 …
Convert inches to feet by dividing by 12, so 9 ft 6 in is 9.5 ft. The calculator accepts 9' 6" directly.
Square feet to linear feet
linear feet = square feet ÷ material width (ft) = square feet × 12 ÷ width (in)
For 200 ft² of decking with boards 5.5 in wide: 200 × 12 ÷ 5.5 = 436.4 linear feet. Use the actual face width, not the nominal size, and add the gap for spaced boards.
Worked example: baseboard for a bedroom
A 14 ft × 12 ft bedroom has a 3 ft doorway in one of the 12 ft walls, so the runs are 14 ft twice, 12 ft once and 9 ft once. Baseboard comes in 16 ft pieces at $18.50 each, and we allow 10% for mistakes:
- Total length: 14 ft × 2 + 12 ft + 9 ft = 49 ft
- With allowance: 49 ft × 1.1 = 53.9 ft
- Cut list: fitting each length into 16 ft pieces needs 4
- Pieces: larger of the cut list and length ÷ stock = 4
Buy 4 pieces of 16 ft for about $74.00. Notice the cut list matters: each wall wants one unbroken piece, so the short offcuts cannot be joined into a new wall. Open this example in the calculator.
Linear feet per 100 square feet
How many linear feet of material cover 100 ft² at common actual board widths (no gaps):
| Face width | Linear feet per 100 ft² | Typical use |
|---|---|---|
| 2.5 in | 480 ft | 1×3 trim, narrow flooring |
| 3.5 in | 342.9 ft | 1×4 or 2×4 |
| 5.5 in | 218.2 ft | 1×6 or 5/4×6 deck boards |
| 7.25 in | 165.5 ft | 1×8 |
| 9.25 in | 129.7 ft | 1×10 |
| 11.25 in | 106.7 ft | 1×12 |
Buying material by the linear foot
- Plan the cuts, not just the total. Four 5 ft runs total 20 ft, which looks like 2.5 pieces of 8 ft stock, but only one 5 ft run fits in each 8 ft piece, so you need four. Enter each run separately so the calculator can plan the cut list.
- Buy the longest practical stock for long walls to avoid joints; joins in trim and baseboard should fall on studs.
- Prices per linear foot and per piece are both common. If the store prices per piece, enter the stock length and choose Per piece.
- Lumber by volume is sold in board feet; use the board foot calculator for hardwood priced that way.
Assumptions and limitations
- The cut list places the longest runs first and fills leftover space in earlier pieces; runs longer than a piece are made from full pieces plus a remainder.
- Saw kerf (about 1/8 in per cut) and miter angles are not deducted; the allowance covers them for most trim jobs.
- Area to linear feet assumes material laid edge to edge. For spaced decking or siding with overlap, adjust the width.
Linear feet questions
How do I calculate linear feet?
Measure each length in feet and add them. For a room, that is the length of each wall (minus doorways, if the material stops there). A 12 × 10 ft room has 12 + 10 + 12 + 10 = 44 linear feet of wall.
How many linear feet are in a square foot?
It depends on the width of the material. A 12 in wide board covers one square foot per linear foot; a 6 in board needs 2 linear feet per square foot. Divide 12 by the width in inches.
Is a linear foot the same as a foot?
Yes. A linear foot is 12 inches of length. The word “linear” just makes clear you are measuring length only, not area (square feet) or volume (cubic or board feet).
How many 8 ft boards do I need for 100 linear feet?
100 ÷ 8 = 12.5, so at least 13 boards, plus an allowance. If the runs are shorter than 8 ft, plan the cuts: offcuts often cannot be reused.
How do I convert linear feet to meters?
Multiply by 0.3048. 100 linear feet is 30.48 meters. Switch the calculator to metric to work in meters throughout.
Formulas, unit conversions and default values are explained on our methodology page. Results are estimates; check manufacturer data and local codes before you buy or build.