How do I calculate siding for a house?

Measure the height and width of each exterior wall and multiply to get total square footage. Subtract the area of all windows and doors. Add 10-15% for waste and cuts, then divide by the coverage per panel or square to determine how much siding to order.

How many squares of siding do I need?

Calculate the total wall area in square feet, subtract openings (windows and doors), and divide by 100 to convert to squares. One square equals 100 square feet of coverage. Add 10-15% for waste depending on the complexity of your home's exterior.

What is a siding square?

A siding square is a unit of measurement equal to 100 square feet of wall coverage. Siding manufacturers package and price material by the square. For example, a house with 2,000 square feet of exterior wall area (minus openings) would need about 20 squares of siding.

How do I account for windows and doors in siding calculations?

Measure the width and height of each window and door, then multiply to get the area of each opening. Subtract the total opening area from your gross wall square footage. For a rough estimate, a standard window is about 15 square feet and a door is about 20 square feet.

How much siding do I need for a 2,000 sq ft house?

A 2,000 sq ft single-story house typically has about 1,400-1,800 sq ft of siding area (after subtracting openings). Plan for 14-18 squares of siding. Two-story homes of the same floor plan have ~2,800-3,400 sq ft of siding. Always order 10-15% waste for cuts, dormers, and damaged pieces.

What's a 'square' of siding?

100 square feet. Vinyl siding is sold by the box, where each box typically contains 2 squares (200 sq ft). Fiber cement, wood lap, and engineered wood are typically sold by the piece or board. Always confirm with your supplier whether their quote is per box, per square, or per piece — the same job can quote at wildly different totals depending on the unit.

Do I need house wrap under siding?

Yes — code requires house wrap (Tyvek or similar) behind all siding on most new construction and is highly recommended on residing jobs. It provides moisture barrier, prevents wind infiltration, and meets building code in nearly all US jurisdictions. One roll (9' × 100' or 3' × 165') covers 900-1000 sq ft. Skipping house wrap fails inspection in most municipalities.

How long does siding installation take?

Vinyl siding: experienced installer averages 1 square per hour solo, 1.5-2 squares per hour with a 2-person crew. Fiber cement (HardiePlank): roughly half that speed because of weight, cutting requirements, and dust management. Wood lap and engineered: 60-70% of vinyl speed. A typical 1,800 sq ft house (18 squares) is a 1-2 day vinyl job or 3-4 day fiber cement job for a 2-person crew.

Should I overlap siding seams or use H-channels?

For vinyl: overlapping seams (1 inch overlap minimum, with manufacturer-specified expansion gap) is standard practice and uses less material than H-channel splice trim. H-channels look cleaner but cost more and become visible joint lines. Long walls (over 30 ft) commonly use a mix: H-channels at architectural breaks (corners, windows) and overlaps mid-wall. Wood and fiber cement use butt joints over studs with backer caulking — no H-channel needed.

Siding Calculator

Calculate siding materials, trim, starter strip, J-channel, corner posts, and fasteners needed for your project. Supports vinyl, fiber cement, wood lap, and board and batten siding.

Siding Type

Waste Factor (%)

Wall Measurements

Walls:

Wall 1ft H ×ft W

Wall 2ft H ×ft W

Wall 3ft H ×ft W

Wall 4ft H ×ft W

Gable Ends (Optional)

Gables:

No gable ends. Increase the count above to add triangular gable areas.

Doors (standard 3' × 7')

Windows (standard 3' × 5')

Outside Corner Posts

Inside Corner Posts

Material List

Total Wall Area

1,260

sq ft (incl. gables)

Openings Subtracted

162

sq ft (2 doors, 8 windows)

Net Siding Area

1,098

11.0 squares

Vinyl Siding

box (2 squares)

Starter Strip

140

linear ft (12 pieces @ 12')

J-Channel / Trim

162

linear ft (13 pieces @ 12.5')

Outside Corner Posts

~9 ft tall each

Inside Corner Posts

~9 ft tall each

Nails / Fasteners

2,718

~16 lbs

Estimated Labor

11 hrs

≈ 2 days (1 installer)

Material Prices (for cost estimate)

Siding ($/box)

Trim ($/lin ft)

Corner Posts ($/each)

House Wrap ($/roll)

Include house wrap (required by code in most jurisdictions)

Material Shopping List

Vinyl Siding

13 boxs$1235

Starter strip + J-channel + trim

302 lin ft$861

Corner posts (outside + inside)

4 posts$112

House wrap rolls (9' × 100')

2 rolls$330

Galvanized nails (1.5")

16 lbs$192

Estimated Material Cost$2730

Pro Tips

Order house wrap with the siding, not separately. Most lumber yards bundle pricing when you order both. The same roll bought a week later costs 15-20% more.
Vinyl tip: Order an extra box beyond your calculated quantity. Vinyl colors can vary slightly between manufacturing runs, and matching becomes impossible if you run short mid-job. Returns are accepted up to 30 days at most suppliers.
10% waste assumes simple walls. If your project has dormers, complex rooflines, multiple gables, or non-90-degree corners, bump to 15%.
Plan delivery carefully. Most lumber yards charge $75-$200 delivery; siding bundles are awkward to handle, especially fiber cement (a single piece weighs 5-8 lbs). Avoid having the truck dump in a wet area — saturated bundles warp.
Check siding gauge / quality tier.Vinyl ranges from .040" (cheap, budget) to .055" (premium). Fiber cement has Standard vs ColorPlus vs ArtisanLap tiers. The same square footage can vary 2-3x in cost depending on tier — make sure you're comparing apples to apples.
Inside corners are sometimes optional on vinyl with J-channel installation, but always required on fiber cement and wood lap. Adjust your corner count by trade type.

Did this help?

How to Use This Calculator

Enter the number of walls and their dimensions (height x width). Add gable ends if your home has triangular areas above walls. Specify doors and windows to subtract from the total wall area. Choose your siding type and waste factor, then review the complete material list below.

Formula Used

Net Area = (Sum of Wall Areas + Gable Areas) - Door Openings - Window Openings. Pieces/Boxes = Net Area x (1 + Waste%) / Coverage per Unit. Starter Strip = Sum of Wall Widths. J-Channel = Window Perimeters + Door Perimeters.

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Disclaimer

This calculator is for estimation purposes only. Results may vary based on local conditions, materials, and building codes. Always consult a licensed professional before making decisions based on these calculations. MyContractorTools is not responsible for any errors or omissions.