WallsELEVATION
Enter a perimeter and a wall height.
Perimeter is the distance all the way around the house at ground level: add up every wall. Wall height is the ground to the soffit, not to the ridge. Gables go in the next box.
GablesTRIANGLES
A gable is a triangle: base x height / 2. Base width is the wall below it, peak height is from the top of that wall up to the ridge. Enter 0 gables for a hip roof, where every side is a slope and there are no triangles to cover.
OpeningsDEDUCT
Estimators normally deduct only the big holes. A standard window is smaller than the offcut you create by siding around it, so deducting it leaves you short. A garage door or a wall of glass is big enough to matter. Sizes used here are averages: 3x5 window, 3x7 door, 16x7 garage door.
MaterialBOXES
Corners & Trim StockLIN FT
Unrolled ElevationTO SCALE
Every wall laid end to end as one strip, with the gable triangles and the openings drawn to scale. This is the shape you are actually buying siding for.
ResultsLIVE
Squares to buy
0.00 squares
1 square = 100 sq ft
| Trim | Linear ft | Pieces |
|---|---|---|
| Starter strip | 0.0 | 0 |
| Outside corner posts | 0.0 | 0 |
| Inside corner posts | 0.0 | 0 |
| J-channel, openings | 0.0 | 0 |
| Top run and gable rakes | 0.0 | 0 |
| Battens | 0.0 | 0 |
Enter a perimeter and height and the full working shows here.
Waste allowance
Materials Ticket#SIDING
Enter a perimeter and wall height to build your ticket.
Quote in squares, buy in boxes or pieces. Both lines are on the ticket, along with the trim, which is where siding jobs usually go over budget.
How This Is Calculated
- Wall area = perimeter x wall height. Perimeter is every wall added up at ground level, height is ground to soffit.
- Gables = base x peak height / 2, times the number of gables. A gable is a triangle, so it is half of what the rectangle would be.
- Openings are deducted according to your rule. Under trade practice only openings over 32 sq ft come out, because the offcut you create siding around a normal window is worth more than the hole.
- Base siding area = walls + gables - openings. Waste is added on its own line and never folded in.
- Squares = total to buy / 100. That is the unit siding is quoted in, and it is why a quote of "18 squares" means 1,800 sq ft.
- Boxes or pieces = total to buy / coverage per unit, rounded up. Leftover is what those whole units cover above your target.
Trim is separate from the field siding and is quoted in linear feet. Starter strip runs the perimeter once. Corner posts run the full wall height at each corner. J-channel goes around every window and door, and along the top run and the gable rakes. Rake length per side is sqrt((base / 2)^2 + peak height^2), so a 30 ft gable rising 8 ft has 17 ft rakes.
Coverage per box or per piece varies by profile and by exposure, so it is an input rather than a fixed assumption. The reference table below gives the usual figures as a sanity check.
Quick ReferenceSCREENSHOT ME
Typical coverage by siding type
| Material | Sold as | Typical coverage | Notes |
|---|---|---|---|
| Vinyl lap | Box | 2 squares (200 sq ft) | The industry standard carton. Double 4 and double 5 profiles both usually box at 2 squares. |
| Fiber cement lap | Piece, 12 ft | 6 to 8 sq ft per board | Coverage is 12 ft x exposure. A 8.25 in board at 7 in exposure covers 7.0 sq ft. |
| Engineered wood lap | Piece, 16 ft | 8 to 10.7 sq ft per board | A 16 ft board at 6.75 in exposure covers 9.0 sq ft. Wider 12 in boards cover more. |
| Board and batten panel | Panel, 4x8 | 32 sq ft per panel | Plus battens: linear feet equals wall height times the number of batten lines. |
| Cedar shingle | Bundle | 25 sq ft at 5 in exposure | Coverage changes with exposure, so confirm the exposure before counting bundles. |
Coverage depends on the exposure, which is the amount of each board left visible after the next one laps over it. Change the exposure and the coverage changes with it, so read the product page for the exact profile you are buying.
Squares to square feet
| Squares | Square feet | Roughly |
|---|---|---|
| 10 | 1,000 | Small ranch, one story, simple roof |
| 15 | 1,500 | Typical one story with two gables |
| 20 | 2,000 | Two story box, or a large one story |
| 25 | 2,500 | Two story with gables and a garage wing |
| 30 | 3,000 | Large two story, several rooflines |
Costing the job next? See the siding cost guide for what a square actually costs installed by material.
Related Calculators
- Square FootageL-shapes & odd rooms
- FlooringBoxes of plank
- TileTiles, boxes, grout
- Siding CostCost per square
- RoofingSquares & bundles
- InsulationBatts & R-value
- PaintGallons per coat
- DrywallSheets, mud, tape
- DeckBoards & joists
- FencePosts, rails, pickets
- ConcreteBags & yards
- GravelTons & yards
- PaversPavers, sand, base
- Cubic YardAny depth of fill
Siding Calculator FAQ
What is a square of siding?
What is a square of siding?
A square is 100 square feet of finished wall. It is the unit siding is quoted, sold and installed in, which is why a contractor says "this is an 18 square job" rather than 1,800 square feet.
Vinyl siding is usually cartoned at two squares per box, so an 18 square job is 9 boxes before waste. Roofing uses the same 100 sq ft square, which is why the two trades talk the same way.
How do I measure a gable?
How do I measure a gable?
A gable is a triangle, so it is base x height / 2. The base is the width of the wall underneath it and the height is from the top of that wall straight up to the ridge, not along the slope.
Measure it from the ground with a tape on the wall below and a bit of arithmetic rather than on a ladder: if the roof is a 6 in 12 pitch and the gable is 30 ft wide, the peak is 15 x 6/12 = 7.5 ft above the wall top. A hip roof has no gables at all, so enter zero.
Do I subtract windows and doors from siding?
Do I subtract windows and doors from siding?
Only the big ones. The standard trade practice is to deduct openings over about 32 square feet, which means a garage door or a sliding glass wall comes out but a normal window does not. Cutting siding around a window creates offcuts you cannot use elsewhere, so the material you "save" by deducting it is material you then have to buy back.
This calculator defaults to that rule and shows you exactly what came out. If you would rather deduct everything or nothing, switch the rule and watch the base area change. That is the honest way to handle a genuinely contested assumption.
How many boxes of vinyl siding do I need?
How many boxes of vinyl siding do I need?
Divide the total to buy by the coverage of one box and round up. A standard vinyl carton covers two squares, or 200 sq ft, so a house needing 1,584 sq ft after waste takes 1,584 / 200 = 7.92, which is 8 boxes.
Check the carton before you commit. Coverage is driven by the exposure of the profile, and a double 4 carton and a double 5 carton do not always hold the same square footage even from the same brand.
How much waste should I add for siding?
How much waste should I add for siding?
Ten percent for a simple boxy house with four corners and a straight roofline. Fifteen percent once you have dormers, several corners or a wing. Twenty percent for many gables, angled walls, bays, or anywhere a lot of courses die into a rake and every board gets cut twice.
Gable ends are the worst offenders because every course meets the rake at an angle. If most of your area is gable, use the higher figure even on a simple plan.
How much trim do I need for a siding job?
How much trim do I need for a siding job?
Starter strip runs the perimeter once at the bottom. Corner posts run the full wall height at every outside and inside corner. J-channel goes around every window and door, along the top of the walls under the soffit, and up both rakes of every gable.
The trim table above works all of that out in linear feet and then converts it to whole pieces at the length you buy them in, which is usually 10 ft for corner posts and 12 ft 6 in for J-channel. Trim is where siding budgets quietly blow up, so price it before you order the field siding.
Does siding go over the old siding?
Does siding go over the old siding?
Sometimes, and the answer changes your material count only slightly, but it changes your trim and fastener count a lot. Going over existing siding usually requires furring to get a flat plane, longer fasteners, and trim built out to meet the new depth around windows.
Your local code and the manufacturer's installation instructions both have a say, and installing outside the written instructions can void the warranty. Confirm both before you buy.
What does a square of siding cost?
What does a square of siding cost?
It varies enormously by material, region and whether it is installed or material only, which is why this calculator asks for your own price rather than inventing one. Put the price of one box or one piece into the material box above and the ticket prices your own job.
For current ranges by material and what drives an installed quote up or down, read the siding cost guide.