Siding Calculator — Vinyl & Fiber Cement Sq Ft, Squares & Boxes
Estimate how much siding you need for a whole house. Enter each wall, choose vinyl or fiber-cement lap, subtract doors and windows, and add waste to get net square footage, squares (100 sq ft), boxes, and the number of planks — with a downloadable takeoff PDF.
| Wall | Dimensions | Area | Squares |
|---|---|---|---|
| Run the calculator to see your takeoff | |||
How to use the siding calculator
Four quick steps turn your wall dimensions into net square footage, squares, boxes, and planks — for vinyl or fiber-cement lap siding — with a downloadable takeoff.
Pick material & coverage
Choose vinyl or fiber cement, then set the coverage per box, exposure, and plank length to match your product.
Add your walls
Enter each wall as width × height, with a quantity for identical walls. Mark triangular ends as Gable — the half is applied.
Deduct openings & waste
Subtract the total area of large doors and windows, then dial in a waste factor for cuts and corners.
Read results & save a PDF
Get net area, squares, boxes, and planks, plus a wall-by-wall breakdown — then download a two-page takeoff.
How a siding estimate is calculated
Siding starts with net wall area, then converts to squares, boxes, and planks. Here is the exact math the calculator runs, from raw walls to the number you order.
Worked example — four walls (32×9, 32×9, 26×9, 26×9), 120 ft² openings, vinyl, 10% waste
Gross area: 288 + 288 + 234 + 234 = 1,044 ft²
Net: 1,044 − 120 = 924 ft² · With 10% waste: ≈ 1,016 ft²
Squares: 1,016 / 100 = 10.2 · Boxes: 1,016 / 200 → 6
Planks (8″ exp × 12 ft = 8 ft² each): 1,016 / 8 → 128
Order 6 boxes of vinyl — about 10.2 squares, or 128 planks.
Siding estimating charts
Handy lookups for coverage units, typical opening deductions, squares and boxes by house size, and waste factors. Coverage and exposure vary by brand — check your product’s label.
| Unit | Coverage | Notes |
|---|---|---|
| 1 square | 100 ft² | Standard estimating unit |
| Vinyl box | ~200 ft² | About 2 squares per box |
| Fiber cement | 100 ft² | Often ordered by the square |
| Plank — 8″ exp × 12 ft | 8 ft² | Typical double-4 vinyl |
| Plank — 7″ exp × 12 ft | 7 ft² | Typical 8¼″ fiber-cement lap |
Coverage per plank = (exposure ÷ 12) × plank length. Box coverage varies by brand and profile — use your label’s figure.
| Opening | Typical size | Area |
|---|---|---|
| Window (average) | 3 × 5 ft | ~15 ft² |
| Entry door | 3 × 6.75 ft | ~20 ft² |
| Patio / sliding door | 6 × 6.75 ft | ~40 ft² |
| Single garage door | 9 × 7 ft | ~63 ft² |
| Double garage door | 16 × 7 ft | ~112 ft² |
Deduct the big openings; small windows are often left in as built-in waste. Larger two-car doors can run up to ~140 ft².
| Net wall area | With 10% waste | Squares | Vinyl boxes (200 ft²) |
|---|---|---|---|
| 800 ft² | 880 ft² | 8.8 | 5 boxes |
| 1,000 ft² | 1,100 ft² | 11.0 | 6 boxes |
| 1,200 ft² | 1,320 ft² | 13.2 | 7 boxes |
| 1,500 ft² | 1,650 ft² | 16.5 | 9 boxes |
| 2,000 ft² | 2,200 ft² | 22.0 | 11 boxes |
| 2,500 ft² | 2,750 ft² | 27.5 | 14 boxes |
Boxes round up and assume 200 ft² per box. For fiber cement ordered by the square, use the squares column and round up.
| House shape | Waste factor | Why |
|---|---|---|
| Simple box, few corners | ~10% | Long straight runs |
| Average house | 10–12% | Standard corners & openings |
| Many corners, gables, dormers | 15% | Lots of angle cuts |
| Diagonal or board-and-batten | 15%+ | More offcuts & layout waste |
Waste covers cuts, corners, and damaged pieces. Trim and accessories are ordered separately, by the linear foot.
Everything the calculator works out
One set of walls gives you every number needed to order and price the siding — from net area to the exact boxes or planks to buy.
Key figures every siding takeoff depends on
Built for any siding job
From re-siding one elevation to a whole-house wrap, the same calculator scales to the walls.
Re-siding a wall or a small home and wants the exact boxes and squares to buy without over-ordering.
- Enter each wall width × height
- Deduct the big openings
- Add 10% waste and get boxes
Pricing a full re-side fast, with gables handled correctly and squares ready for the bid.
- Batch identical walls with Qty
- Mark gable ends for the ½ rule
- Hand the PDF takeoff to the yard
Rolling siding into a project budget where squares and boxes drive the material cost.
- Compare vinyl vs fiber-cement units
- Set coverage & exposure per product
- Read net area, squares & planks
7 tips for an accurate siding order
Siding is bought in fixed units and matched dye lots, so a careful takeoff saves both a short order and a color-mismatched reorder. These habits keep your count honest.
Siding calculator FAQ
The area, coverage, and ordering questions people ask most before buying siding.
Add up the area of every wall, subtract the big openings, then add a waste factor.
Each rectangular wall is width × height; a gable is half that (½ × width × height). Total those, subtract doors and windows, and add about 10%.
Example: 1,044 ft² of wall − 120 ft² openings = 924 ft² net, about 1,016 ft² with 10% waste, or roughly 10.2 squares.
One square of siding covers 100 square feet. It’s the standard unit siding and roofing are estimated in, because it keeps the math simple across brands.
To convert, divide your area to cover by 100 — 1,016 ft² is 10.16 squares.
Vinyl is usually sold by the box (often about 2 squares, or 200 ft²), while fiber cement is commonly ordered by the square or counted by the plank.
Divide your total area to cover (net area plus waste) by the coverage per box, then round up.
A standard vinyl box covers about 200 ft² — two squares. So 1,016 ÷ 200 = 5.08 → 6 boxes.
Coverage per box varies by brand and profile, so check the label and enter your actual box coverage for an accurate count.
A gable is the triangular wall under a pitched roof, and its area is half of a rectangle: ½ × width × height.
Measure the full width at the bottom of the triangle and the vertical height from that base to the peak, then multiply and halve. A gable 24 ft wide and 6 ft tall = ½ × 24 × 6 = 72 ft².
Enter it as a Gable in the calculator and the half is applied automatically.
Usually only the large ones. Small windows are often left in the total as built-in waste, since you cut siding around them and the offcuts aren’t always reusable.
For big openings — garage doors, sliding doors, walls of glass — subtract the area so you don’t over-order. Typical deductions: ~15 ft² per window, ~20 ft² per entry door, and 100+ ft² for a two-car garage door.
Enter the total opening area to remove, or leave it at zero to side over everything.
A 10% waste factor is typical for a simple, boxy house. Increase it to 15% or more for homes with lots of corners, gables, dormers, or diagonal runs.
Waste covers cuts at corners and openings, offcuts too short to reuse, and the occasional damaged piece. Siding is awkward to reorder in a matching dye lot, so rounding the waste up on cut-up elevations is usually worth it.
The area math is identical — both come down to net wall area plus waste. What differs is how the product is packaged and counted.
Vinyl is usually sold by the box (~200 ft², two squares). Fiber-cement lap is typically ordered by the square (100 ft²) or counted by the plank.
Plank count depends on exposure and length: a 12-ft plank at 8″ exposure covers ~8 ft², at 7″ about 7 ft². Set the material, box coverage, and exposure to match your product.
No. This calculator estimates the field siding — the panels or planks that cover the walls. Trim and accessories are ordered separately.
That includes starter strip, J-channel, inside and outside corner posts, undersill, soffit and fascia, house wrap, fasteners, and any color-matched trim boards.
These are counted by the linear foot or by the piece, not by wall area, so price them on top of the siding count.
Estimating Notice: Actual siding quantities vary with wall layout, course exposure, cutting waste, and how gables and openings are handled. This calculator provides area-based square-footage, square, box, and plank counts from your input — coverage per box, exposure, and waste differ by brand and profile, so always check your product’s label. Trim, corners, starter, soffit, fasteners, and other accessories are not included and must be ordered separately. Confirm all quantities and coverage with your supplier before ordering. For planning purposes only.