Siding Calculator
Enter the total perimeter of the walls and their height, add any gables and subtract doors and windows, and the calculator returns the siding in squares (1 square = 100 ft²) plus the exact boxes, planks or panels to buy for your product. Siding is sold and priced by the square, so that's the number to take to the supplier.
Your measurements
Add up the width of every wall you're siding — the distance all the way around the house.
Floor-to-eave height of the walls. For a two-story house, use the full height.
Vinyl is sold by the box (2 squares each). Lap planks are sold by the piece. Panel and board & batten come in 4×8 sheets.
Siding to buy
13.9 squares
7 boxes · 1,260 ft² net
What to buy
- Siding
- 13.9 squares(1 sq = 100 ft²)
- Vinyl
- 7 boxes
Net wall area with 10% waste, divided by 100. Siding is priced by the square.
Each box covers 2 squares (200 ft²).
Typical installed cost
Installed, materials + labor — a ballpark to sanity-check bids, not a quote. See the cost breakdown.
Estimates only. Verify against your supplier's coverage figures before ordering.
Footprint
Wall elevation to scale
Horizontal lap · 8" exposure
The numbers
- Wall area
- 1,260 ft²
- Net area
- 1,260 ft²
- With waste (+10%)
- 1,386 ft²
Perimeter × height.
What actually gets covered.
The area to buy siding for.
The formula
Net area = perimeter × height + gables − openings · Squares = net area × (1 + waste) ÷ 100 · Vinyl boxes = ⌈squares ÷ 2⌉ · Lap planks = ⌈area ÷ (exposure⁄12 × length)⌉ · Panels = ⌈area ÷ 32⌉
Example: A house with 140 ft of wall perimeter at 9 ft tall is 1,260 ft². With 10% waste that's about 13.9 squares — 7 boxes of vinyl.
How it works
- 1Find the wall area: add up the perimeter of every wall you're siding and multiply by the wall height.
- 2Add the gable ends and dormers (each triangle is base × height ÷ 2), then subtract the doors and windows.
- 3Add 10% for waste on straightforward walls — 12–15% for cut-up walls or shake-style products — then divide by 100 to get squares.
- 4Convert squares to the unit you buy: vinyl comes in boxes of 2 squares; lap siding by the plank (exposure × length per piece); panel and board & batten in 4×8 sheets.
- 5Order the trim separately — starter strip, J-channel, corner posts and fasteners aren't counted in the field squares.
Frequently asked questions
How much siding do I need?
Multiply your total wall perimeter by the wall height, add gables, subtract doors and windows, add about 10% waste, then divide by 100 for squares. A 1,260 ft² house is about 13.9 squares with waste.
What is a square of siding?
A square is 100 square feet of coverage — the unit siding is sold and priced in. So 2,000 ft² of wall is 20 squares before waste. Vinyl typically comes in boxes of 2 squares (200 ft²).
How many squares of siding for a 2,000 sq ft house?
It depends on wall area, not floor area. A 2,000 ft² two-story home often has 1,800–2,400 ft² of wall — roughly 20–26 squares after openings and 10% waste. Measure your actual walls for an exact figure.
How much extra siding should I buy for waste?
Add 10% for straightforward horizontal lap on simple walls, 12% for vertical or board-and-batten, and up to 15% for shake-style siding or cut-up, multi-corner walls.