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Siding Calculator

Enter your wall dimensions to estimate siding in squares (100 ft²) and panels, with a waste allowance for cuts and trim. Subtract windows and doors for a tighter material count.

You need approximately
4 squares
covers 352 ft² (incl. waste)
Area to cover
352 ft²
Exact amount
3.52 squares

Field notes

Waste climbs with corners, not square footage. A plain gable end runs 10%; a house with dormers, bays, and multiple gables can waste 15% because every angled cut leaves an unusable offcut. Measure each wall separately and subtract only the big openings — trying to net out every window invites a shortfall. Buy one extra square and keep it for storm repairs; dye lots shift between orders.

How the siding calculator works

The math behind the tool:

wall area ft² = Σ(wall height × wall length) − openings
squares = wall area ÷ 100 × (1 + waste%)

Sources: Polymeric Exteriors Alliance (formerly Vinyl Siding Institute) (siding coverage and installation standards).

Frequently asked questions

How many squares of siding do I need?

Divide your total wall area (in ft²) by 100 to get siding squares, then add 10% for waste. A 1,500 ft² wall area needs about 16.5 squares of siding.

How much waste should I add for siding?

Add about 10% for straight walls and 15% for homes with many corners, gables, or dormers, since angled cuts create more offcuts.

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