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How to Measure for Siding on a House

Measure your house for siding the right way — which walls, how to handle gables, and the mistakes that blow an order.

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)

A practical measuring walk-around

Grab a tape (a laser measure helps for tall walls), a notepad, and walk the house one elevation at a time. For each flat wall, record width and height. For the triangular gable sections up under the roof, record the base and the height to the peak. Note every window, door and garage opening with its size. That notepad is all the calculator needs.

The two classic errors are forgetting the gables and measuring height to the wrong line. Measure walls from the bottom of the siding to the eave, and treat the gable as a separate triangle on top. Do that and your takeoff will match the pro's.

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)

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.

What to write down

For each surface: width × height (walls), base × rise (gables), and size × count (openings). That's the entire dataset a siding estimate needs — everything else is arithmetic.

The basis for the math

Nothing here is a black box. Wall area minus the openings gives net coverage; dividing by 100 gives squares, the unit the trade orders in; a waste percentage accounts for the pieces you cut and can't reuse. Those steps are industry standard. The per-product coverage and the cost bands are drawn from manufacturer installation data and commonly cited US pricing, so they're representative rather than exact for your ZIP code. Use the result to plan, then verify with your supplier.

Getting the order right the first time

Your result above answers the main question. Before you buy, run through the practical points that most affect a how to measure for siding on a house 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 measure my house for siding?

Measure each wall's width and height, each gable's base and rise, and every opening's size. Enter them above and the tool converts to area, squares and materials.

Do I measure to the peak of the roof?

Measure the rectangular wall to the eave, then add the gable triangle separately from the eave line up to the peak. Don't measure one tall rectangle to the peak.

What tools do I need to measure?

A tape measure or laser measure, a notepad, and a ladder for reachable heights. For tall or steep walls, a laser measure from the ground is safest.

How do I handle a two-story wall?

Measure the full height from siding bottom to eave, or add per-floor lines — the area is the same. Add gables above as triangles.