Siding Calculator
Wall area less openings, then lap siding by the piece from its exposure or panel siding by the sheet, with gables counted as triangles.
Quick answer: lap siding by exposure
| Exposure | Lineal ft per 100 ft² | 12 ft pieces per 1,000 ft² | 16 ft pieces |
|---|---|---|---|
| 4 in. | 300 ft | 275 | 207 |
| 5 in. | 240 ft | 220 | 165 |
| 6 in. | 200 ft | 184 | 138 |
| 7 in. | 171 ft | 158 | 118 |
| 8 in. | 150 ft | 138 | 104 |
Lineal feet = wall area × 12 ÷ exposure, with 10 % waste in the piece counts. Exposure is what shows, not the board's width; read it on the product sheet. The calculator deducts 21 ft² per door and 15 ft² per window first.
| Wall area, gross | — |
|---|---|
| Gables | — |
| Openings deducted | — |
| Net siding area | — |
| With waste | — |
| Lap siding | — |
| Panel siding | — |
Exposure is the number that turns area into pieces. A lap board 8 inches wide shows less than 8 inches. The overlap hides the rest. What is left showing is the exposure, and that is what covers the wall. Linear feet = area × 12 ÷ exposure: 969 square feet at an 8-inch exposure is 1,453 linear feet, and at 6 inches it is 1,938. Read the exposure off the product. It is the single figure this page cannot guess.
Gables are triangles, and there are usually two. Half the width times the rise, each. A 28-foot gable rising 7 feet is 98 square feet; two of them are a fifth of a small house’s wall. Left out, the order comes up one wall short and the colour lot may not match when the rest arrives.
Openings come off, corners and trim go on. A door is about 21 square feet, a window about 15; the page deducts them. What it does not add is the corner boards, J-channel, starter strip and trim that a real siding order carries. Those go by the linear foot of edge, from the same perimeter and heights.
Vinyl siding hangs on its nails; it is not nailed tight. The Vinyl Siding Institute's 2020 quick tips ask for about 1/32 in., the thickness of a dime, between the fastener head and the nail hem, fasteners long enough to penetrate at least 1-1/4 in. into sheathing and framing, at most 16 in. apart on siding and 8 to 12 in. on accessories, and no face-nailing except the one nail that finishes the top of a gable.
Every receiving channel takes a gap, and the weather sets it. Leave 1/4 in. inside all receiving channels at openings and stops, and 3/8 in. (9.5 mm) when installing below 40 °F, because the panels are cut at the length they have that day. Where panels overlap they overlap 1 in. on the face, lapped away from entrances and from the point of greatest traffic.
The laps are siding the wall never shows. A 1 in. end lap on a 12 ft panel is 0.7% of the panel, and every end joint in a course takes one; the waste row covers them, not the area. The VSI tips are general, and the panel maker's own instructions govern where they differ, as the tips themselves say.
What I check on a job
Check what the two inputs measure. Before I trust the piece count I check what the two inputs measure. Perimeter times eave height assumes every wall is clad from the same line to the same line, and few houses are. Where the foundation steps with the grade, the sided height changes along the wall, so I take the height wall by wall. Walls under a porch roof or behind an attached garage may not be sided at all, and I take them out of the perimeter. Then the openings. The page deducts 21 ft² per door and 15 per window, which suits ordinary units; a garage door or a run of patio doors is far larger, so I deduct it by hand at its real size or the order comes out long. Last, the piece length against the wall runs. When the runs don't divide well into 12, 16 or 20 feet, offcuts pile up faster than a flat percentage assumes, so I lay the lengths against the real walls before I trust the waste figure.
Gross wall = perimeter × eave height; gables = ½ width × rise each; openings at 21 ft² per door and 15 ft² per window (the same nominal sizes the drywall and paint pages use). Lap siding linear feet = net area × 12 ÷ exposure; pieces = linear feet ÷ piece length, rounded up; panels = area ÷ 32 ft², rounded up. Waste is applied before the piece counts.
Worked example
A house with 120 ft of perimeter and 9 ft walls, one door and six windows, in 8-inch-exposure lap siding: how many pieces?
- Gross wall 120 × 9 = 1,080 ft²; less a door (21) and six windows (90): 969 ft².
- With 10% waste, 1,065.9 ft²; at an 8 in exposure that is 1,065.9 × 12 ÷ 8 = 1,599 linear feet.
- In 12 ft pieces: 134. As 4 × 8 panels instead: 34 sheets.
134 twelve-foot pieces. Add two 28 × 7 gables and the net wall becomes 1,165 ft² — the gables are the wall most often left off the order.
13 values on this page were driven in a browser and compared with independently derived figures on 2026-10-29 (2808 values across 228 calculators site-wide).
Questions
How much siding do I need for a house?
Perimeter × wall height, plus the gables (½ width × rise each), minus doors and windows, plus about 10% waste. For lap siding, area × 12 ÷ exposure gives the linear feet; 969 ft² at an 8 in exposure is about 1,600 linear feet with waste.
What is siding exposure?
The part of each board that shows once the next one overlaps it. It is smaller than the board width and it is the number that turns area into pieces.
How much do the gables add?
Half the width times the rise, for each one: a 28 ft gable rising 7 ft is 98 sq ft, and there are usually two, a fifth of a small house's wall. Left out, the order comes up a wall short and the colour lot may not match when the rest arrives.
Does the page count J-channel and corner boards?
No. Corner boards, J-channel, starter strip and trim are sold by the linear foot of edge, from the same perimeter and heights you entered. The page deducts openings (21 sq ft a door, 15 a window) but does not add the trim.