🧩Vinyl Siding Calculator
Get boxes of vinyl siding plus starter strip, J-channel, corner posts and nails.
Your walls
Add each wall as a rectangle and each gable as a triangle (base × height).
You'll need about
4 boxes
6.82 squares (incl. 10% waste) · 6 starter strips · 8 J-channel · 4 corner posts
squares
6.82
J-channel ft
90
starter ft
70
nails (lb)
7
🛒 Shopping list
- Vinyl siding (2-square boxes)4 boxes
- Starter strip (12 ft)6 pieces
- J-channel (12.5 ft)8 pieces
- Outside corner posts (10 ft)4 posts
- Roofing / siding nails7 lb
Leave nails about 1/32 in proud and centered in the slots — vinyl needs room to slide as it warms and cools.
How it works
Area = walls + gables − openings, plus waste. Squares = area ÷ 100; boxes hold 2 squares. Starter strip runs the length of every wall (12 ft pieces). J-channel ≈ 14 ft per door or window plus both gable rakes (12.5 ft pieces). Outside corner posts = corners × (wall height ÷ 10 ft). Nails ≈ 1 lb per square.
Worked example
With 40 × 8 and 30 × 8 ft walls, a 30 × 8 ft gable, 60 sq ft of openings and 10% waste: 6.82 squares = 4 boxes, 6 starter strips, 8 pieces of J-channel (90 ft), 4 corner posts and 7 lb of nails.
Questions people ask
Usually 2, but check your brand — you can change it in admin.
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Last updated October 8, 2026. These results are friendly estimates to help you plan — always double-check before buying or making big decisions.