Siding is sold by the square — 100 sq ft, or 9.29 m². The wall area is the easy part. What sends people back to the yard is everything around it: corners, channel, starter strip and trim, none of which are measured in squares.
Enter the wall area and what one square or box covers. We'll work out the quantity — and list the trim that isn't in it.
Works in metric and US imperial — you choose at the start and can switch at any time. Every figure this calculator uses is published with its source, and the result comes with a printable order sheet. No account, no email, and nothing you type leaves your browser.
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Siding is sold by the square — 100 sq ft, or 9.29 m². What sends people back to the yard is everything around the field of siding: corner posts, J-channel, starter strip and trim, none of which appear in an area calculation. Note also that a square is a unit of area, not a box: a box of vinyl siding is usually two squares, but check, because that assumption is where the count goes wrong.
Half the base times the height. Adding a gable in as a full rectangle over-orders badly on a large elevation — on a 8 m wide gable 3 m high that is 24 m² counted instead of 12. It is the single biggest source of over-ordering on this material.
Vinyl expands and contracts with temperature a great deal, so nails go in the centre of the slot and are not driven tight. Siding fixed hard will buckle in the first hot spell. And remember siding is a rain screen rather than a waterproof layer: what actually keeps water out is the housewrap behind it and the flashing over every opening, both of which go on first. Order in one batch for colour, and keep a box back — matching siding five years later is close to impossible.
By the square — 100 sq ft or 9.29 m2. A box of vinyl siding is usually two squares, but check rather than assume, because that is where counts go wrong.
As a triangle: half the base times the height. Counting a gable as a full rectangle roughly doubles it and is the biggest single cause of over-ordering.
Not tight. Nails go in the centre of the slot and are left slightly loose so the panel can move — vinyl expands and contracts substantially with temperature, and siding fixed hard will buckle in the first hot spell.
Not by itself. Siding is a rain screen; what keeps water out is the housewrap behind it and the flashing over every opening. Both go on before any siding does.