# What is my linear foot total?

Finds linear feet of boards, trim or fencing from square feet and the board width, from a count of pieces, or around a rectangle, with waste, boards to buy and cost.

- Page: https://www.acalculator.org/construction/linear-feet-calculator
- JSON spec: https://www.acalculator.org/construction/linear-feet-calculator.json
- Version: f2359a618873

## Default answer

Example with the default inputs (Start from Square feet, Area to cover 200 ft², Board width 5.5 in, Gap between boards 0.1875 in, Extra for waste 10%): You need 464.18 linear feet (141.48 m).

## Inputs

| Key | Label | Description |
| --- | --- | --- |
| mode | Start from | An area to cover with boards, a number of pieces, or the edge of a rectangle. |
| a | Area to cover | The floor, deck or wall area the boards cover. |
| bw | Board width | The actual face width of one board: a nominal 6 in deck board is 5.5 in. |
| gap | Gap between boards | The space left between boards, such as 3/16 in (0.1875 in) for composite decking. 0 for none. |
| n | Number of pieces | How many pieces there are. |
| pl | Length of each piece | The length of one piece. |
| l | Length | The length of the rectangle. |
| w | Width | The width of the rectangle. |
| waste | Extra for waste | Length to add for cuts, offcuts and mistakes, in percent: 5% to 15% is typical for decking. |
| bl | Board length to buy | The length of the boards you will buy, such as 12 ft or 16 ft. Leave empty to skip. |
| price | Price per linear foot | The price of one foot of length. Leave empty to skip the cost. |

## Outputs

| Key | Label | Description |
| --- | --- | --- |
| linearFeet | Linear feet | The total running length, with the extra for waste, in feet. |
| meters | Linear metres | The same length in metres. |
| yards | Linear yards | The same length in yards (3 ft each). |
| boards | Boards to buy | Linear length ÷ the board length, rounded up to a whole board. |
| cost | Cost | Linear feet × the price per linear foot. |

## Method

Square feet: linear length = area ÷ (board width + gap). Pieces: number × length of each. Perimeter: 2 × (length + width). Then × (1 + waste ÷ 100); boards = length ÷ board length, rounded up; cost = linear feet × price per foot.

## Assumptions

- Extra for waste is 10% by default (TimberTech: add at least 10% to 15%; Trex: about 5%).
- Board width is the actual face width (5.5 in for a nominal 6 in deck board), plus the gap between boards, 3/16 in by default (TimberTech composite decking).
- Boards run the full length with no gaps at the ends; joins and patterns are covered by the waste share.

## Worked examples

1. mode = area, a = 18.580608, bw = 0.1397, gap = 0.004762, waste = 10% gives linearFeet = 464.175824, meters = 141.480791. Source: TimberTech, How to Calculate How Much Decking You Need (5.5 in boards; at least 10% to 15% extra), https://www.timbertech.com/ideas/how-to-calculate-how-much-decking-you-need/.
2. mode = area, a = 13.378038, bw = 0.1524, gap = 0, waste = 0%, bl = 3.6576, price = $2.50 gives linearFeet = 288, yards = 96, boards = 24, cost = $720.00. Source: Trex, How Many Deck Boards Do I Need? (deck depth in inches ÷ board width = boards across), https://www.trex.com/deck-ideas/how-many-deck-boards-do-i-need-/.
3. mode = pieces, n = 12, pl = 2.4384, waste = 0% gives linearFeet = 96, meters = 29.2608. Source: NIST Handbook 44 (2026), Appendix C (1 ft = 0.3048 m).
4. mode = perimeter, l = 6.096, w = 3.6576, waste = 5%, bl = 2.4384 gives linearFeet = 67.2, boards = 9. Source: Trex, How Many Deck Boards Do I Need? (5% extra for waste), https://www.trex.com/deck-ideas/how-many-deck-boards-do-i-need-/.

## FAQ

### What is a linear foot?

A linear foot is simply a foot of length, measured along a board, trim or fence, whatever its width or thickness. Ten 8 ft boards are 80 linear feet.

### How do I convert square feet to linear feet?

Divide the area by the width each board covers, in feet. For a 144 ft² deck of 6 in (0.5 ft) boards with no gap, 144 ÷ 0.5 = 288 linear feet. In inches: 144 × 12 ÷ 6 = 288.

### What board width should I use for decking?

Use the actual face width, not the nominal size: a nominal 6 in deck board (1×6 or 2×6) is 5.5 in wide (Trex). Add the gap between boards; TimberTech asks for at least 1/8 in, and 3/16 in for its composite decking.

### How much extra should I add for waste?

Trex’s rule of thumb is 5% extra; TimberTech suggests at least 10% to 15%, and 30% for diagonal or herringbone patterns. The calculator adds 10% by default.

### How many boards do I need?

Divide the linear feet by the length of the boards you will buy and round up. 288 linear feet of 12 ft boards is 24 boards; of 16 ft boards, 18.

### How do I find linear feet for a fence or baseboard?

Measure the length of each run and add them up. For a rectangle, the perimeter is 2 × (length + width): a 20 × 12 ft yard has 64 ft of edge. Subtract doors or gates you will not cover.

### Are linear feet the same as board feet?

No. Board feet measure volume (12 in × 12 in × 1 in); linear feet measure length only. Use the board foot calculator for lumber priced by volume.

## Sources

- Trex, How Many Deck Boards Do I Need? (5.5 in board width; deck depth ÷ board width; 5% extra for waste). https://www.trex.com/deck-ideas/how-many-deck-boards-do-i-need-/ (retrieved 2026-10-01)
- TimberTech, How to Calculate How Much Decking You Need (5.5 in boards; at least a 1/8 in gap, 3/16 in for composite; add at least 10% to 15%). https://www.timbertech.com/ideas/how-to-calculate-how-much-decking-you-need/ (retrieved 2026-10-01)
- NIST Handbook 44 (2026), Appendix C, General Tables of Units of Measurement: 1 ft = 12 in = 0.3048 m; 1 yd = 3 ft; 1 ft² = 144 in². https://www.nist.gov/document/2026-nist-handbook-44-appendix-c (retrieved 2026-10-01)