Siding calculator
Wall area around the building less the openings, plus the waste corners and butt joints eat.
Siding
Wall area around the building less the openings, plus the waste corners and butt joints eat.
Add trim, corners and starter strip separately — they run 10 to 15 per cent of the siding cost.
$6,195
2,816 sq ft of vinyl at $2.20 / sq ft
Free. No signup. The quantities carry over as line items.
How this siding calculator works
Wall area around the building, less the openings, plus what corners and butt joints eat. The trim package is separate and it is not small.
The formula
area to order = (perimeter × wall height − openings) × (1 + waste)
Assumptions and defaults
| Default waste | 10% |
| Squares | 100 sq ft |
| Trim, corners, starter | 10–15% of siding cost, priced separately |
Pro tips
Measure gable ends as half of base × height and add them. On a two-storey with steep gables that is a real chunk of wall people leave out.
Order starter strip, J-channel and corner posts at the same time as the field siding — colour matching a partial order later rarely goes well.
Fibre cement is heavy. If you are pricing labour off a vinyl job, do not — the hanging rate is roughly half.
Common questions
How do I calculate siding square footage?
Perimeter times wall height gives gross wall area. Subtract windows and doors, then add waste. This calculator does all three.
Should I deduct windows from siding?
Deduct the big openings, keep the small ones in as waste allowance. Garage doors and picture windows are worth taking out; a single bathroom window is not.
How much extra siding should I order?
Ten per cent on a simple box. Fifteen if the elevation has a lot of corners, dormers or cut-ups, because every corner is two cuts.
What is a square of siding?
100 square feet, the same unit roofers use. Vinyl is often sold in squares; fibre cement and engineered wood by the piece or the foot.