Siding Squares Chart by Perimeter and Wall Height
Ten wall perimeters against six wall heights, with the waste already added, so you can price the walls before you have measured a single gable.
Siding is sold and quoted in squares. A square is 100 square feet, a carton of vinyl covers two of them, and the number a supply house wants when you call an order in is squares rather than square feet.
The number that drives it is perimeter, not floor area. A 1,500 square foot house can have a 160 foot perimeter if it is close to a rectangle, or well over 220 if it has bump outs, a wing and a wrapped porch, and the siding follows the wall rather than the floor. Measure the outside of the building and add it up.
Every figure below is walls only, with 12 percent waste in it. Gables are a separate table on the gable area chart, and openings come off at half once you have counted them.
Siding squares by wall perimeter and wall height
| Wall perimeter | 8 ft walls | 9 ft walls | 10 ft walls | 16 ft walls | 18 ft walls | 20 ft walls |
|---|---|---|---|---|---|---|
| 100 ft | 9 | 10.1 | 11.2 | 17.9 | 20.2 | 22.4 |
| 120 ft | 10.8 | 12.1 | 13.4 | 21.5 | 24.2 | 26.9 |
| 140 ft | 12.5 | 14.1 | 15.7 | 25.1 | 28.2 | 31.4 |
| 160 ft | 14.3 | 16.1 | 17.9 | 28.7 | 32.3 | 35.8 |
| 180 ft | 16.1 | 18.1 | 20.2 | 32.3 | 36.3 | 40.3 |
| 200 ft | 17.9 | 20.2 | 22.4 | 35.8 | 40.3 | 44.8 |
| 220 ft | 19.7 | 22.2 | 24.6 | 39.4 | 44.4 | 49.3 |
| 240 ft | 21.5 | 24.2 | 26.9 | 43 | 48.4 | 53.8 |
| 260 ft | 23.3 | 26.2 | 29.1 | 46.6 | 52.4 | 58.2 |
| 280 ft | 25.1 | 28.2 | 31.4 | 50.2 | 56.4 | 62.7 |
The same walls in full, at 9 foot walls
| Wall perimeter | Wall area, sq ft | With 12% waste, sq ft | Squares | Cartons at 2 squares | Starter strip, ft |
|---|---|---|---|---|---|
| 100 ft | 900 | 1,008 | 10.1 | 6 | 100 |
| 120 ft | 1,080 | 1,210 | 12.1 | 7 | 120 |
| 140 ft | 1,260 | 1,411 | 14.1 | 8 | 140 |
| 160 ft | 1,440 | 1,613 | 16.1 | 9 | 160 |
| 180 ft | 1,620 | 1,814 | 18.1 | 10 | 180 |
| 200 ft | 1,800 | 2,016 | 20.2 | 11 | 200 |
| 220 ft | 1,980 | 2,218 | 22.2 | 12 | 220 |
| 240 ft | 2,160 | 2,419 | 24.2 | 13 | 240 |
| 260 ft | 2,340 | 2,621 | 26.2 | 14 | 260 |
| 280 ft | 2,520 | 2,822 | 28.2 | 15 | 280 |
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The siding calculator takes your own measurements and returns the number for your job, plus the material list as a printable document. Every cell in the table above came out of that same calculator, run at build time.
Measure the perimeter, not the square footage
Walk the outside of the house with a tape and write down every wall, including the jogs. A bump out that is four feet deep adds eight feet of perimeter, four out and four back, and it adds nothing at all to the floor area you would read off a listing.
A 160 foot perimeter at nine foot walls is 16.1 squares and a 200 foot one is 20.2, four squares apart on two houses that could list at the same floor area. Perimeter is the measurement, and it is worth taking properly.
Wall height on a two story is more than two times nine
A two story wall is the first floor, the band joist between the floors, and the second floor, which usually lands at 18 or 19 feet rather than the 18 you get by doubling a nine foot wall. Measure from the bottom of the starter strip to the underside of the soffit and use that.
Anything over about twenty feet is staging or a lift rather than ladder work. That does not change the material, but it changes the labor and the schedule, and it changes them before the material line moves at all.
What the table leaves out on purpose
Gables, because they are triangles and they deserve their own table. Openings, because they come off at half rather than in full and the count is yours to make. Soffit and fascia, because they are bought by the foot rather than the square.
Add the gables from the gable area chart, take half the opening area off, and what is left is the order. The siding calculator does all three at once if you would rather type the numbers in than add them up.
Questions people ask
How many squares of siding do I need for a 2,000 square foot house?
About 20 squares for a typical single story with a 180 foot perimeter, nine foot walls and two gables. Find your perimeter in the table above for the wall portion, add the gables separately, then take half the window and door area back off.
How many square feet does a box of vinyl siding cover?
Two hundred, which is two squares. Fiber cement and wood lap are sold by the piece rather than by the carton, so use the square figure and convert at whatever coverage your supplier lists.
Why is 12 percent waste the default?
It is what a straightforward elevation actually runs. Every course that meets a corner, a window or a gable rake leaves an offcut too short to start the next wall with. A cut up front, a wrapped bay or shake courses in the gable want 15 percent, and a plain rectangle with few openings can sometimes come in under 10.
Do I need house wrap under siding?
Yes on any new wall and on nearly every re-side, both as a water resistive barrier and because most codes require one behind the cladding. Buy it by the gross wall area including the gables, before any opening is deducted, because it goes on continuously and gets cut afterwards.