Siding Calculator

Measure the perimeter of your home (all exterior wall widths) and multiply by the exposed wall height. Add the area of any triangular gables (base × peak height ÷ 2). Subtract door and window openings. Multiply by (1 + waste factor — usually 5–15%). That gives you the order area. Divide by 100 to get squares, or by carton coverage to get boxes needed.

A 'square' is the standard construction unit for siding, roofing, and other exterior materials. One square equals 100 square feet of material coverage. Most vinyl siding cartons contain 2 squares (200 sq ft). When contractors quote 'per square,' they mean per 100 sq ft of installed coverage.

Vinyl siding typically comes in boxes containing 200 sq ft (2 squares). Fiber cement (HardiePlank) varies by profile — usually 150–200 sq ft per carton. Metal siding and board & batten often come in bundles that cover 100–250 sq ft depending on the exposure. Always check the manufacturer's label — 'nominal' board size differs from 'installed exposure' due to overlap.

A gable is a triangle: measure the base width (usually the same as the wall below the gable) and the vertical peak height from the eave line to the top of the roof ridge. Gable area = base × peak height ÷ 2. Do NOT use the sloped rafter length — use vertical height only. This is the #1 mistake DIYers make.

Simple rectangular elevations: 5%. Typical home with gables and a few windows: 10% (industry standard). Complex roofs, lots of corners, mixed profiles: 12–15%. Historic/complex with many angles: 15–20%. Also add a safety buffer — siding color batches change quarterly, so order 5–10% extra to guarantee color match if repairs are needed later.

Yes — subtract the measured area (width × height) of every door, window, and garage door from your gross wall area. The resulting 'net area' is what actually gets covered with siding. However, you still need J-channel, flashing, and trim around each opening — those are calculated separately as accessories, not subtracted.

Vinyl siding: $200–$500 per square (material only, installed $500–$1,200/sq). Fiber cement (HardiePlank): $300–$800 per square material, $1,000–$2,000 installed. Metal/steel siding: $400–$900 per square material, $800–$1,500 installed. Wood siding: $500–$1,500+ per square installed. Prices vary by region, profile, and whether old siding needs removal.

Divide your net order area by the coverage per board. Coverage per board = (exposure in inches ÷ 12) × board length in feet. Example: 6-inch exposure × 12-foot board = 6/12 × 12 = 6 sq ft per board. 2,000 sq ft ÷ 6 = 334 boards needed. Round up — you can't buy partial boards.

Exposure is the width of each siding board that is visible after overlapping the board below. A 12-inch wide board with 8-inch exposure means 4 inches overlaps the lower board. The exposure directly determines how many rows of siding you need and how many cartons to buy. Never use the nominal board width — always use the installed exposure.

Most building codes require a water-resistive barrier (WRB / housewrap) between the sheathing and the siding. Standard roll coverage is 150–200 sq ft per roll. You need one roll per roughly 150 sq ft of wall area (add 10% for overlap). Our calculator doesn't include housewrap automatically — add it as a separate line item in your estimate.

J-channel: count the perimeter of every window and door opening plus the bottom of every wall — that's your total linear feet. Inside/outside corners: count each corner of your home and multiply by the wall height. Standard pieces come in 10ft or 12ft lengths — round up to whole pieces. The trim section of our calculator handles this automatically.

Yes — the core area calculation (walls + gables − openings + waste) works for every siding material: vinyl, fiber cement, wood, metal, brick, stucco. What changes is the profile/exposure (affecting boards and cartons), waste factor (metal with ribbed profiles might need less waste), and price per sq ft. Pick your profile from the dropdown for preset carton coverage, or override it to match your supplier's numbers.

As a rule of thumb, wall area runs about 1.2× the home's living area once gables are counted and openings deducted. A 1,500 sq ft home has roughly 1,800 sq ft of wall — about 20 squares with 10% waste. Most homes land between 12 and 28 squares: two-story homes sit at the low end, rambling ranches at the high end. See our quick-reference tables below for size-by-size estimates.

Openings under about 25 sq ft (a typical 3×4 window is 12 sq ft) can safely stay in your takeoff — the J-channel, casing, and cut-offs around them roughly offset the material you save. Always deduct large openings: garage doors, patio sliders, and picture windows. Our calculator lets you deduct everything for the tightest possible number.

Boxes = order area ÷ coverage per box (standard vinyl cartons cover 200 sq ft — round up). Pieces = order area ÷ per-board coverage, where per-board coverage = (exposure in inches ÷ 12) × board length in feet. Example: a 1,711 sq ft order needs 9 vinyl boxes, or about 285 boards at 6 sq ft each.

Nominal width is the full board width before installation — a '6-inch' cedar board actually dresses down to 5½ inches at the mill. Exposure is what stays visible after each board laps the one below, typically 1 to 1½ inches less again. Coverage math must use exposure: a 6″ board at 4½″ exposure covers 25% less than its nominal width suggests.

The cost estimate covers field siding material, plus labor and tear-off if you enter those rates. Housewrap, soffit, fascia, flashing, sealants, and fasteners are separate line items — and installed labor typically adds 60–100% on top of material cost depending on region and story height. See the trim & accessories section above for the full checklist.

Keep 1–2 unopened boxes from your original order. Manufacturers retire and reformulate colors every few years, so an exact match five years from now is often impossible — the box in your garage is your warranty. Store it flat, indoors, away from heat sources (vinyl warps near heat).

Yes — horizontal lap profiles are exactly what the board-count math is built for. Enter your installed exposure and board length, and the calculator converts net area into per-board coverage, total boards, and cartons. It works the same for vinyl lap, Dutch lap, fiber cement plank, and wood clapboard — only the per-piece coverage changes.

Every triangle uses base × vertical peak height ÷ 2 — the calculator applies it automatically to each gable section you add. Skip the ÷2 and a 24 ft × 5 ft gable doubles from 60 to 120 sq ft of phantom siding. Measure the rise straight up from the eave line to the ridge, never along the sloped rafter.

Big-box tools estimate squares for the products each store stocks. This one accepts any supplier's carton coverage, exposure, and pricing, then itemizes squares, boxes, trim, labor, and tear-off. Many contractors run both and compare — when the numbers differ, it's almost always carton coverage or a missing waste factor.

Menards quotes siding by the square in-store and through its project services, but the takeoff math is universal: walls + gables − openings + waste. Run your numbers here first, then hand Menards — or any lumber yard — a firm square and carton count, and they can price any brand they carry against it.