Siding Calculator
Enter your wall area and the openings to deduct to estimate siding squares and an optional cost.
Results
- Siding squares
- 12.1 squares
- Net wall area
- 1,100 sq ft
- Area incl. waste
- 1,210 sq ft
Estimates only. Round up and buy a little extra to account for waste, spills, and breakage.
Siding is ordered in squares, where one square equals 100 square feet. This calculator converts wall area minus openings into squares, boxes and trim footage.
Vinyl siding usually ships two squares per box, so most orders round to the nearest half box in practice.
Also works as a vinyl siding calculator, siding squares calculator, and lap siding estimator.
How to use the siding calculator
- Enter the wall perimeter in ft.
- Enter the wall height in ft.
- Enter the doors & windows.
- Enter the waste factor in %.
- Optionally add a price to estimate the total project cost.
- Read your quantities instantly — no sign-up, and you can print the estimate to take to the supplier.
Worked example
Inputs
- Wall perimeter
- 140 ft
- Wall height
- 9 ft
- Doors & windows
- 8
- Waste factor
- 10 %
Results
- Siding squares
- 12.1 squares
- Net wall area
- 1,100 sq ft
- Area incl. waste
- 1,210 sq ft
Using the example values above, the siding calculator returns 12.1 squares (siding squares). Change any field to match your own project and the numbers update instantly.
Measuring walls and gables
Rectangular walls are length times height. A gable is half the base times the height, so a 24 ft wide gable rising 8 ft adds 96 square feet.
Subtract only large openings such as garage doors and picture windows. Leaving standard windows and doors in the total conveniently covers cutting waste.
Waste and trim
Add 10 percent waste for a simple rectangular house and 15 percent for homes with dormers, bays and multiple gables.
Do not forget accessories: J channel around every window and door, starter strip along the bottom of every wall, inside and outside corner posts, and undersill trim at the top course.
How much extra should I order?
Always order a little extra. A 5% waste factor suits simple, square projects; 10% is right for most jobs; bump it to 15–20% for irregular shapes, diagonal patterns, or uneven ground. Running short almost always costs more than the leftover material.
Cubic yard coverage by depth
| Depth | Coverage per cu yd |
|---|---|
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
Formula
Net area = wall area − openings. Squares = net area ÷ 100, × (1 + waste%).
Frequently asked questions
- How much siding waste should I plan for?
- Add 10% for simple walls and up to 15% for homes with many corners and gables.
- What is a square of siding?
- A square covers 100 square feet of wall, the same unit used for roofing.
- How many squares of siding do I need?
- Total wall area in square feet divided by 100, plus 10 to 15 percent waste. A 2,000 sq ft wall area is 20 squares plus waste.
- How much siding is in a box?
- Most vinyl siding boxes hold two squares, which is 200 square feet of coverage.
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How Much Siding Do I Need?
Estimate siding squares for your home's walls, including openings and waste.