How Much Vinyl Siding Do I Need?
Tell the calculator your wall sizes and it answers the only question that matters at the store: how many boxes of vinyl to buy.
Walls (feet)
Gables / triangles optional
Windows & doors to subtract
Tip: measure each wall's width × height at its widest points. A per-wall audit table appears below so you can check every number.
Your siding squares, panels and cost appear here.
Estimated from wall count and perimeter — confirm against your actual corners and openings.
Cost per sq ft: – · per square: –
| Surface | Area (sq ft) |
|---|
From measurements to a shopping list
If this is your first re-side, the jargon can be off-putting — squares, reveals, starter strip. Ignore all of it for a moment. The job is simply to measure your walls, take out the holes, and add a little extra. This page walks you through exactly that and hands back a plain shopping list: boxes of siding plus the trim pieces.
Work around the house one wall at a time. Add a line for the front, the back and each side. If a wall has a triangular section up under the roof, that's a gable — add it separately with its base and height. Then list your windows and the doors. Press calculate and you're done.
Getting an estimate in a couple of minutes
There's no learning curve here. Enter what you measured and the tool does the conversions; the only judgment call is the waste percentage. Start by choosing your material at the top of the form, since that sets the coverage the math relies on. Then add your walls one line at a time — front, back and both sides — typing each width, height and quantity.
Next, deal with the parts a plain rectangle misses: add any gable as its base and rise, and subtract each window and door by size and count. Finally, set a waste allowance (10% for a simple house, more for a cut-up one) and, if you want a budget, turn on the cost fields. The result — squares, panels, boxes, accessories and price — updates as soon as you calculate, ready to print, copy or share.
A quick gut-check
Rough rule of thumb before you measure: a one-story house is often 12–18 squares; a two-story is frequently 22–30. Your real number depends on wall height and how many openings you have, so use the tool for anything you're about to buy.
About the accuracy of these results
We'd rather be transparent than falsely precise. The quantity math is deterministic and matches standard takeoff practice, so if your inputs are right, your squares and piece counts are right. Where real-world variation lives — coverage by profile, and installed cost by region and crew — we use typical published figures and present them as ranges. That makes this a strong planning number, not a binding quote; a contractor's field measure remains the final word.
A few things worth confirming first
Your result above answers the main question. Before you buy, run through the practical points that most affect a how much vinyl siding do i need project, so the number translates cleanly into a real order.
- Confirm coverage: the default coverage is a planning figure. Check the exact coverage printed on your product's box or spec sheet and adjust it if it differs, since even a small change moves the piece count on a big wall.
- Match the waste to your walls: keep 10% for a simple rectangular house, and raise it toward 15% for gables, dormers, bay windows and lots of angled cuts, because those details generate short offcuts you can't reuse.
- Account for accessories: starter strip, trim, inside and outside corners, flashing and fasteners are all part of a complete order, not an afterthought — the takeoff above estimates each so your material list is whole.
- Keep a spare: hold back a piece or a full box for future repairs, since profiles and colors get discontinued over time and an exact match years later is hard to find.
- Time your order: have material delivered close to the start date, stored flat and dry, so it isn't sitting exposed or getting damaged before the crew arrives.
Re-run the numbers above after any change and lean on the per-wall audit to verify each surface one at a time, so what you order matches what the wall actually needs rather than a rough guess. That small habit is the difference between one clean delivery and a mid-project trip back to the supplier.
Frequently asked questions
How many boxes of vinyl siding do I need?
Should I buy extra vinyl siding?
Do I measure to the peak on a gable wall?
What if my walls are different heights?
What users tell us
"I had zero idea where to start. This made it a 10-minute job and the count was spot on."