How this calculator works
This runs our siding calculator on your measurements. The wall area is the perimeter times the height plus the triangular gables, less the openings; siding is sold in squares of 100 ft², and a lap piece covers its length times its exposure. House wrap covers the whole wall, and corner posts and J-channel follow the corners and the edges of the openings.
Worked example: a house with a 140 ft perimeter, 9 ft walls, two 28 × 8 ft gables and 150 ft² of openings has 1,334 ft² to cover. It needs 14.7 squares of siding with 10% waste (210 lap pieces of 12 ft at 7 in exposure), 12 starter strips, 2 rolls of house wrap, 4 corner posts and 10 pieces of J-channel.
Siding by house size (9 ft walls, two 28 × 8 ft gables, 150 ft² of openings, 7 in exposure)
With 10% waste.
| Distance around | Siding | Pieces of 12 ft | House wrap rolls |
|---|---|---|---|
| 100 ft | 10.7 squares | 154 | 2 |
| 120 ft | 12.7 squares | 182 | 2 |
| 140 ft | 14.7 squares | 210 | 2 |
| 180 ft | 18.6 squares | 267 | 3 |
| 220 ft | 22.6 squares | 323 | 3 |
Tips before you buy
- Install the house wrap and flashing properly: water behind siding is the main cause of rot, so lap each layer over the one below it.
- Siding expands and contracts with temperature. Leave the gaps the maker specifies and do not nail it tight.
- Buy all the siding from one lot, since colors vary, and allow for the finishing trim and soffits too.
- Vinyl is best installed in mild weather, and fiber-cement needs a saw with a dust-collecting blade.
- Take photos of the old wall as you strip it, so that you know where wiring and pipes run.
Tools & materials for this project
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Frequently asked questions
How much siding do I need for my house?
For a 140 ft perimeter with 9 ft walls, two gables and 150 ft² of openings: 14.7 squares with 10% waste. A taller 18 ft two-story house with a 180 ft perimeter needs 35.4.
How many pieces of vinyl siding in a square?
A square is 100 ft². A 12 ft piece at 7 inch exposure covers 7 ft², so there are about 15 pieces in a square.
How much house wrap do I need?
2 rolls of 9 × 100 ft (900 ft²) for a house with 1,334 ft² of wall, with 10% for laps.
Do I need J-channel and corner posts?
Yes for vinyl: J-channel around windows and doors (10 pieces here), and corner posts at each outside corner (4 here).
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Related calculators & guides
Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.