Skip to content
CostToUpgrade
CalculatorsCost GuidesCost DataMethodology Search Browse calculators
Siding & Exterior

Siding Calculator

Siding is ordered by the square — 100 square feet of finished coverage — and vinyl ships two squares to a box. Enter your wall area, gable triangles, and the large window and door openings you want deducted to get the exact squares, boxes, and material cost for the job.

Reviewed by The CostToUpgrade Estimating Desk Last reviewed How we estimate

Your project

Dimensions

Total wall area — length × height for each wall. Measure gables separately below.

Each gable triangle = ½ × width × height. Two 24 ft gables 8 ft tall ≈ 190 ft².

Deduct only openings over ~10 ft². A window is ≈ 15 ft², an entry door ≈ 21 ft².

Material

10% for straight lap runs; 15% for shake, board-and-batten, or lots of gables.

Pricing

Vinyl material runs ≈ $150–$400 per square; fiber cement ≈ $400–$700.

Estimate

17.82squares

Siding needed · 1 square = 100 ft² of coverage

Net area to cover
1,620ft²
Boxes of vinyl siding
9boxes
Estimated material cost
$4,633.20

Estimates are guidance only and exclude tax, labor, and site conditions unless stated. Confirm with a local pro.

How it's calculated

No black boxes — here is the exact math behind your estimate, so you can check it or adapt it for your own quote.

  1. 1Net area (ft²) = wall area + gable area − openings deducted
  2. 2Squares = (net area ÷ 100) × (1 + waste% ÷ 100)
  3. 3Boxes = ⌈ squares ÷ 2 ⌉ (vinyl ships 2 squares per box)
  4. 4Cost = squares × price per square

Worked example

A two-story house with 1,600 ft² of wall, 200 ft² of gable, and 180 ft² of windows and doors deducted, at 10% waste.

Inputs

Wall area
1600 ft²
Gable area
200 ft²
Openings to deduct
180 ft²
Waste allowance
10 %
Price per square
260 $/square

Result

Siding needed
17.82 squares
Net area to cover
1,620 ft²
Boxes of vinyl siding
9 boxes
Estimated material cost
$4,633.20

Tools & materials for this project

As an Amazon Associate we may earn from qualifying purchases, at no extra cost to you.

  • Snap lock punch Punch tabs in cut panels so the top course locks under the undersill trim.
    View on Amazon
  • Siding removal (zip) tool Unlock existing courses to patch or work behind panels without breaking them.
    View on Amazon
Get real quotes

Compare local pros for new siding

An estimate gets you a budget. A few competing quotes get you the real price. Tell us about the job and we'll help you find vetted contractors nearby.

Get matched

Siding cost by state

The calculator does the quantity math exactly. What it can't know is what a fair unit price looks like where you live — new siding runs 61% more in the priciest US market than the cheapest.

Siding cost in all 50 states + DC US average $260 per square of siding material · regional averages, full ranked table, and typical project totals.

Frequently asked questions

What is a “square” of siding?
A square is 100 square feet of finished coverage — the same unit roofers use. A house with 1,600 ft² of wall works out to 16 squares before waste. Vinyl lap siding is boxed two squares to a carton, typically 24 panels of double-4 profile at 12 ft 6 in long, which is why the box count here is always half the squares rounded up. Fiber cement and engineered wood are sold by the plank instead, but suppliers still quote the job in squares, so this is the number to take to the counter.
Which windows and doors should I deduct?
Deduct full-size openings only. Standard estimating practice is to subtract anything larger than about 10 square feet and ignore everything smaller, because the offcuts around a small window are too short to reuse elsewhere on the wall. Plenty of estimators deduct nothing at all and treat every opening as built-in waste. A typical house has 10–14 windows at roughly 15 ft² each plus two 21 ft² doors, so 180 ft² is a sensible default. When in doubt, deduct less — running one course short on the last wall costs far more than an extra box.
How much waste should I add?
Ten percent covers a straightforward lap job on a simple rectangular house. Push it to 12–15% when the walls have more cuts than field — multiple gables, dormers, bump-outs, or a lot of trim to cut around. Shake and shingle panels want 15% because the staggered butt edges scrap more of each course, and board-and-batten or any siding run over a steep rake can reach 15–20%. Dropping to 5% only makes sense on a plain gable-end wall where you can plan every cut before you start.
Does this include starter strip, J-channel, and corner posts?
No. Starter strip, J-channel, outside and inside corner posts, undersill, and utility trim are all sold by the linear foot or in 10 ft and 12 ft 6 in sticks and are quoted separately from the field siding. Plan on starter strip along the entire bottom of the house, J-channel around the full perimeter of every window and door, and a corner post at every corner — commonly another 10–20% on top of the siding material bill. Housewrap, flashing, and stainless or hot-dip nails are extra again.
What does new siding cost?
At the $260-per-square material average used here, an 18-square house is roughly $4,700 in siding alone. Builder-grade vinyl runs $150–$250 per square, insulated vinyl and fiber cement $400–$700. Installed cost — labor, housewrap, trim, tear-off, and disposal — typically runs two to three times the material figure, so an average two-story home lands around $9,000–$18,000. Tear-off of existing siding, rotten sheathing found underneath, and lead-safe work practices on pre-1978 homes all add to that, so get itemized bids rather than a lump-sum number.

Related calculators

Siding & Exterior

Soffit and Fascia Calculator

Open calculator

Siding & Exterior

Gutter Calculator

Open calculator

Flooring

Square Footage Calculator

Open calculator

Concrete

Asphalt Driveway Calculator

Open calculator