Vinyl Siding Calculator
Calculate siding, trim, and accessories for your home exterior.
This tool is for informational and educational purposes only. It is not a substitute for professional financial, medical, legal, or engineering advice. See Terms of Service.
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Request a ToolHow to Use the Vinyl Siding Calculator
This calculator estimates squares of vinyl siding, panel count, and all major trim pieces for a rectangular house. Here is how to get an accurate estimate:
- Enter your house footprint. Measure the exterior length and width of your house in feet. For an L-shaped or irregular house, break it into rectangles and add the results.
- Set your wall height. Measure from the top of the foundation to the bottom of the roof line. Most single-story homes are 8-10 feet. Two-story homes typically run 18-20 feet total.
- Add your gable ends. If your roof has gable ends (triangular peaks), enter the height of each gable triangle and the number of gables. The calculator treats each gable as a triangle with the house width as its base.
- Subtract doors and windows. Enter the number of standard exterior doors (estimated at 21 sq ft each) and windows (estimated at 15 sq ft each). This keeps you from buying siding you will not use.
- Set your waste factor. The default 10% accounts for cuts at corners, around openings, and at the roofline. Increase to 15% for complex trim work or a first-time installation.
- Read your results. The primary result is squares of siding (1 square = 100 sq ft, the standard unit siding is sold by). The breakdown shows individual panel count, starter strip, J-channel, and corner posts.
Results update instantly as you type. Use the Share button to send your inputs to a siding contractor, or Copy to paste the result into a shopping list.
About the Vinyl Siding Calculator
Vinyl siding is sold by the square, where one square covers 100 square feet of wall area. A typical 2,000-square-foot home with 9-foot walls and standard gable ends needs roughly 12-16 squares of siding after openings are subtracted. Individual panels are usually 12 feet long with a 4-inch or 5-inch exposure, covering about 12.5 square feet per panel when installed at standard overlap.
Beyond the siding itself, every installation requires starter strip along the bottom course, J-channel around every window and door opening, and corner posts at all four building corners. For a clean estimate, measure your openings accurately: a standard entry door is roughly 3x7 feet (21 sq ft) and a typical double-hung window is about 3x5 feet (15 sq ft). All calculations run entirely in your browser. No data is stored or transmitted.
Frequently Asked Questions
How many squares of siding do I need for a 1,500 sq ft house?
A 1,500 sq ft house (roughly 40x38 feet) with 9-foot walls, two gable ends at 4-foot height, two doors, and eight windows needs about 12-14 squares of vinyl siding with a 10% waste factor. The exact number depends on your wall height, gable size, and number of openings. Use the calculator above with your actual dimensions for the most accurate estimate.
What is a square of vinyl siding?
One square of siding covers 100 square feet of wall area. Siding manufacturers package panels so that each box or bundle contains one square. This makes it straightforward to order: if you need 15 squares, buy 15 boxes. Squares are the standard unit used by contractors and suppliers across North America.
Do I need to subtract windows and doors when calculating siding?
Yes, subtracting openings prevents you from over-ordering, which saves money. Standard practice is to deduct 21 square feet per door and 15 square feet per window. Some contractors skip the deduction on smaller projects as a built-in buffer, but on large homes with many windows this can add up to several squares worth of unnecessary material.
What trim pieces do I need besides the siding panels?
A complete vinyl siding installation requires starter strip along the bottom course (one linear foot per foot of building perimeter), J-channel around every window and door (measure the perimeter of each opening), corner posts at every outside corner (typically four for a rectangular house), and inside corner posts if your design has re-entrant corners. You may also need under-sill trim, frieze board, and soffit panels depending on your eave style.