What is a siding square?

One siding square equals 100 square feet of wall coverage.

Should windows and doors be subtracted?

Yes for net area, but do not remove every small opening if the installer expects extra cut waste.

Does this estimate J-channel?

Yes, it estimates J-channel or similar trim in linear feet, but exact trim depends on the siding system and opening details.

Siding Calculator

Estimate siding squares, panels, J-channel, starter strip, outside corners, trim, waste and material cost for vinyl or similar siding projects.

Siding material

Common low-maintenance vinyl siding · full 9 in / exposure 8 in · length 12 ft · 0.18 lb/sq ft

House dimensions

Wall perimeter, ft

Wall height, ft

Gable area, sq ft

Openings

Windows

Window width, ft

Window height, ft

Doors

Door width, ft

Door height, ft

Outside corners

Inside corners

Waste, %

Panel price, $/sq ft

Wall preview: horizontal siding rows (15 rows)

Estimate siding squares, panels and trim

English siding searches focus on square footage, siding squares, panel count and trim pieces such as J-channel, starter strip and outside corners. Openings and waste should be part of the estimate.

N e t A r e a = W a l l A r e a - O p e nin g s

S i d in g S q u a r es = \frac{N e t A r e a \times ( 1 + W a s t e )}{100}

P an e l s = ⌈ \frac{N e t A r e a \times ( 1 + W a s t e )}{P an e l C o v er a g e} ⌉

Trim and installation notes

J-channel, starter strip, corner posts, utility trim and soffit/fascia are estimated separately from siding panels.
Vinyl, fiber cement, engineered wood and metal siding use different coverage, waste and accessory rules.
Follow manufacturer instructions for expansion gaps, flashing, fasteners and water-resistive barriers.

Frequently Asked Questions

Sources and References

Calculations are based on the listed reference sources. Links open in a new tab.

Updated: May 29, 2026

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