15 squares
Siding Calculator
Enter your wall perimeter, height, gables, and openings once and get siding squares to buy alongside a concrete estimate for any slab or footing work on the same exterior job.
Material ListSiding squares Starter strip Corner posts Waste-adjusted concrete Bag count
Siding takeoffs live or die on net wall area — gross wall area plus gable triangles, minus every door and window opening, before waste is applied. This page runs that net-area math and, separately, a slab or footing concrete estimate for exterior work that often rides along with a siding job (an entry stoop, a small pad). Each calculator below is the same one available on its own page — nothing here is a new formula.
Estimating siding material
Wall perimeter times wall height gives gross wall area. Gable triangles (half base times height, one per gable end) add to that. Every door and window opening then subtracts from the total, since siding doesn’t get installed over an opening. What’s left is net area, which this calculator converts into “squares” — the trade unit most siding products are sold and estimated in, where one square covers 100 sq ft.
Measure perimeter along the actual wall line at the base of the structure, and measure each opening’s width and height directly rather than assuming a standard size — window and door rough openings vary enough between jobs that an assumed size introduces real error into the takeoff.
Wall dimensions, openings, and slab/footing
Enter wall perimeter, height, gables, and opening areas once for the Siding takeoff below. Slab/footing fields are separate since a concrete pour tied to exterior work isn't sized from wall dimensions.
Siding
Net wall area and siding squares to buy from wall perimeter, height, gables, and openings.
You'll need 15 panels of siding for 1,299 sq ft of wall.
You'll need
Siding result
140 linear ft
36 linear ft
Detail values
- Gross wall area
- 1,260 sq ft
- Gable area
- 90 sq ft
- Net area
- 1,299 sq ft
Assumptions
- Material: Vinyl
- Corner count: 4
- Waste: 10% (editable)
Concrete
Slab or footing concrete volume and optional bag count for exterior work tied to this job.
Order 0.27 cu yd of concrete for this pour.
Order
Concrete result
0.27 cu yd
0 bags
Warnings
- INFO Material estimate only. Footing depth, size, reinforcement, frost depth, and bearing capacity must be verified locally.
Detail values
- Cubic feet
- 6.6
- Cubic yards
- 0.24
- Waste-adjusted cubic yards
- 0.27
- Bag count
- 0
- Effective depth (incl. frost line)
- 0.33 ft
Assumptions
- Concrete density for bag estimate: 4050 lb per cubic yard
- Bag mode enabled: No
Formula details
- Rectangular volume: length x width x depth
- Round volume: pi x radius^2 x depth
- Cubic yards: cubicFeet / 27
- Bag count: ceil((wasteAdjustedCubicYards x 4050) / bagSize)
Why the waste factor matters more on siding than it looks
Siding waste covers more than offcuts: lap siding loses material to overlap and to matching courses around corners and openings, panel products lose material to alignment on irregular wall lengths, and any job with more corners or a more complex roofline needs a higher waste percent than a simple rectangular wall. CrewMeasure starts at 10%, but that number is always shown and editable rather than baked silently into the squares total.
Accessory linear footage (trim, J-channel, starter strip) tracks wall perimeter directly and is reported alongside the squares total, but this calculator does not attempt to itemize individual trim pieces — that still needs a manual count against the specific trim package you’re installing.
Openings, trim, and where this calculator stops
Net area only removes the flat opening area from the wall — it does not add back the extra material J-channel and trim details around each opening actually consume, which is one reason the waste percent exists as a visible, editable input rather than a fixed constant. Corner posts, window/door trim boards, and soffit/fascia are separate material lines this calculator does not estimate.
A slab or footing poured as part of the same exterior job (an entry landing, a small equipment pad) uses its own dimensions, entered separately below, and runs through the same Concrete calculator available on its own page.
FAQ
Does the slab/footing size come from the wall dimensions?
No. Slab length, width, and depth are entered separately from the wall perimeter and height, since a concrete pour tied to exterior work (an entry pad or footing) isn't sized from the wall dimensions above it.
Can I fine-tune just the siding or concrete numbers?
Yes. Flip either section to "Manual entry" to edit its inputs directly without changing the other calculator.
How many gables can I enter?
This page starts with the gables you enter in the master input list; each gable's base and height are entered separately since a building can have gable ends of different sizes.
Does this calculator itemize trim pieces?
No. It reports accessory linear footage tied to wall perimeter, but individual trim pieces (corner posts, window/door trim, J-channel counts) still need a manual count against your specific trim package.
Disclaimer
Material estimate and general reference only. Verify manufacturer coverage rates, local code, and field conditions before ordering or starting work.