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Gable Square Footage Calculator

Get the square footage of any gable end from its base and height — then convert to squares for ordering.

Your Measurements

Units

Siding material

Walls (feet)

Gables / triangles optional

Windows & doors to subtract

Waste allowance (%)

Material price / sq ft ($)

Estimate installed cost (labor + removal)

Labor / sq ft ($)

Old-siding removal / sq ft ($)

Tip: measure each wall's width × height at its widest points. A per-wall audit table appears below so you can check every number.

▤Enter your walls and press Calculate.
Your siding squares, panels and cost appear here.

Panels / boards

–

Order (boxes)

–

Gross area

– sq ft

Openings removed

– sq ft

Accessories takeoff

Estimated from wall count and perimeter — confirm against your actual corners and openings.

Installed cost range

Low

–

Likely

–

High

–

Cost per sq ft: – · per square: –

Per-wall audit

Surface	Area (sq ft)

Just the gable, precisely

Sometimes you already have your wall square footage and only need the gable piece to finish the total, or you're siding a gable on its own as an accent. This page focuses purely on the triangle: give it the base and the rise and it returns the square footage and squares. Add several if your roof has multiple gables or dormers.

It's the same half-base-times-rise formula behind the main calculator, isolated so you can grab just the gable number and slot it into whatever estimate you're building.

Net wall area = Σ (wall width × height) + Σ gables − Σ openings Order area = Net area × (1 + waste %) Squares = Order area ÷ 100 Panels = Order area ÷ coverage per panel (rounded up)

How to fill it in (and what each field does)

Every field maps to a real measurement, so if you can read a tape you can use this. Walk through it top to bottom:

Units + material: feet or meters, then the product you're installing — this sets coverage and a starting price.
Walls: add a row per wall face with its width, height and count.
Gables: base and rise for each triangle under the roof.
Windows & doors: size and count for each, so their area is removed.
Waste & cost: a percentage cushion plus optional labor and removal rates.

Hit calculate and the full breakdown appears below the form.

Multiple gables

Three dormers, each 8 ft base × 4 ft rise: ½ × 8 × 4 = 16 sq ft each, 48 sq ft total. Small individually, but together nearly half a square — worth counting.

Data sources and limitations

Two kinds of numbers feed this tool. The geometry — areas, openings, squares, waste — is fixed arithmetic and as accurate as your tape. The material coverage and the cost estimates are planning values based on common manufacturer specifications and reported US installed pricing; they vary with product line, region and labor, which is why they appear as ranges. Treat the result as a solid starting point for budgeting and ordering, subject to a field measure and your contractor's quote.

Details that make or break the order

Your result above answers the main question. Before you buy, run through the practical points that most affect a gable square footage 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 do I find gable square footage?

Multiply half the base by the rise: ½ × base × height to the peak. Add each gable's area for the total. The tool does this for any number of gables.

What is the base and rise of a gable?

The base is the full width at the eave line; the rise is the vertical height from that line up to the peak. You don't need the sloped rake lengths.

How do I add gable square footage to my walls?

Calculate the gable area here and add it to your wall square footage, then subtract openings. Or use the main calculator, which combines them for you.

Are dormers calculated the same way?

Yes — each dormer face is a small gable. Use the same ½ × base × rise formula and add them up.