Siding Calculator
Free siding calculator. Enter wall dimensions, gables and openings to get squares of siding, vinyl boxes or fiber cement planks, house wrap and trim.
About 9 ft per story
16 × 7 ft door = 112 sq ft
- Squares
- 31.5
- with waste
- Boxes
- 16
- 2 squares per box
- Net wall area
- 2,868 sq ft
- gross 3,120
- Siding cost
- $4,160
Accessories
| House wrap9 × 150 ft rolls | 3 rolls |
| Starter strip12 ft pieces around the base | 14 pcs |
| J-channel12.5 ft pieces around openings (vinyl) | 21 pcs |
| Outside corner posts10 ft posts, four corners | 8 pcs |
Price
$4,160
Siding only, before trim, tax and delivery
Default prices are typical U.S. retail figures, reviewed November 2026. Enter your supplier's prices for an exact total.
Siding is estimated in squares of 100 square feet. Vinyl siding is usually sold in boxes of two squares, while fiber cement lap siding is sold by the plank, and each plank covers only its exposed face once it overlaps the one below.
Enter your house dimensions or the wall area you have measured, subtract windows and doors, and the calculator gives you squares, boxes or planks, plus house wrap, starter strip, J-channel and corner posts.
How to use the siding calculator
- Measure the length of each wall and the height from the foundation to the eaves.
- Multiply length × height for each wall and add them up.
- For each gable end, add width × gable height ÷ 2.
- Subtract garage doors and large openings; small windows can be left in for trim waste.
- Add 10% for waste and divide by 100 to get squares.
Wall area = perimeter × wall height + gables × (width × gable height ÷ 2) − openings. Squares = wall area × 1.10 ÷ 100.
Siding coverage by product
| Product | Exposure | Coverage |
|---|---|---|
| Vinyl, double 4 in | 8 in per panel | 200 sq ft per box (2 squares) |
| Vinyl, double 5 in | 10 in per panel | 200 sq ft per box (2 squares) |
| Fiber cement lap, 6.25 in × 12 ft | 5 in | 5 sq ft per plank |
| Fiber cement lap, 7.25 in × 12 ft | 6 in | 6 sq ft per plank |
| Fiber cement lap, 8.25 in × 12 ft | 7 in | 7 sq ft per plank |
Tips before you buy
- Buy all siding from the same production run so the color matches.
- Leave about 1/4 inch at J-channel and corners for vinyl to expand in summer heat.
- Fiber cement needs special blades or shears and dust control when cutting.
- Order soffit, fascia and trim separately; they are priced by the linear foot.
Frequently asked questions
How do I calculate how much siding I need?
Multiply the length and height of each wall, add the triangle area of each gable, subtract large openings, then add 10% for waste. Divide by 100 for squares.
How much siding do I need for a 2,000 sq ft house?
A two-story 2,000 square foot house usually has about 2,200 to 2,600 square feet of wall, or roughly 22 to 28 squares with waste. A one-story house of the same floor area has less wall.
How many boxes of vinyl siding do I need?
Most vinyl siding boxes hold two squares (200 square feet). Divide your squares by two and round up.
Should I subtract windows when measuring for siding?
Subtract garage doors and very large openings. Most installers leave average windows in because the cutting and trim around them uses up that material.