Siding Calculator
Enter wall length and height to get the wall area and squares of siding to order, with openings deducted.
Walls
Total wall length is the perimeter of the walls being sided. Siding is sold by the square (100 sq ft).
You'll need
Add trim, corner posts, J-channel, and starter strip by linear foot. Order extra for gables and complex elevations.
How to estimate siding
Find the gross wall area (perimeter × height), subtract doors and windows, add ~10% waste, and divide by 100 for squares. Trim, corners, and channel are estimated by linear foot.
Measure the whole exterior from a scan
ProBuildCalc turns your iPhone's LiDAR scanner into a job-site measuring kit — walk the space and it captures the square footage, material takeoff, and a blueprint automatically. No tape measure, no graph paper.
Siding calculator FAQ
- How much siding do I need?
- Multiply the total wall length (perimeter) by the wall height for gross area, subtract doors and windows, add ~10% waste, and divide by 100 for squares. Siding is sold by the square (100 sq ft).
- What is a square of siding?
- A square covers 100 square feet of wall. A box of vinyl siding typically covers two squares (200 sq ft), but check the carton.
- How much waste should I add for siding?
- Plan on about 10% for a simple rectangular house and up to 15% for homes with many gables, corners, and openings that create more cut pieces.
- Do I need to subtract windows and doors?
- Yes — deduct roughly 21 sq ft per door and 15 sq ft per window from the gross wall area, then apply waste to the net.
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See also: estimating guides · ProBuildCalc by trade