Siding Calculator

Siding Calculator works out, in seconds, how many squares of siding a whole house needs — every elevation, the gable triangles, the openings you deduct, the waste you allow, and the trim linear footage that never comes out of the squares. It works completely offline and nothing you enter ever leaves your phone. HOW IT WORKS The app follows the standard whole-house siding take-off: 1. Rectangular wall area comes from the wall perimeter times the storey height times the number of storeys — the sum of every flat elevation in one step, the way an estimator reads a plan. 2. Gable ends are triangles, so each one adds half of base times rise. Measuring a gable as a full rectangle is the classic whole-house over-order. 3. Doors and windows are deducted at their true size, from the counts and sizes you enter. 4. A waste allowance is added for pattern complexity, not for the size of the house: 5 percent on a plain box with long unbroken runs, 10 percent on an ordinary house, 15 to 20 percent once dormers, bays, returns and extra gables leave an offcut at every course. 5. The result is divided by 100 square feet — one square, the unit every siding supplier quotes in — and rounded up to whole squares. 6. Trim and accessories are taken off separately in linear feet: starter strip round the bottom perimeter, a corner post the full height of every corner, J-channel round every window and door, and fascia and soffit along the eaves. A worked example, and the app's default: a 152 ft perimeter, 9 ft storeys, two storeys and two 30 by 7.5 ft gables give 2,736 + 225 = 2,961 sq ft gross. Take off fourteen 3 by 5 ft windows and two 3 by 6.75 ft doors, 250.5 sq ft, and the net is 2,710.5 sq ft. Add 10 percent for a standard house and you buy 2,982 sq ft — 29.82 squares, so 30 whole squares — plus 153 ft of starter, 72 ft of corner posts and 257 ft of J-channel. WHAT YOU CAN DO - Enter the wall perimeter, storey height and storeys and read the squares instantly - Add any number of gable ends by base and rise, computed as true triangles - Deduct windows and doors by count and size, not by guesswork - Pick the pattern complexity and see the waste percentage it implies - Get starter strip, corner posts, J-channel, fascia and soffit in linear feet, plus a nail weight - Open Details for the nine-step take-off, a full trim schedule, and a table that turns the same squares into pieces of vinyl, fiber cement, cedar bevel, engineered wood lap or 4 by 8 panel - Learn why the square is the unit, why gables are half a rectangle, and what the accessories cost you BUILT FOR CLARITY A clean emerald-and-weatherboard design puts the square count first, with the supporting areas and the trim footage right beside it. Light and dark themes, a tiny download, no clutter and no account required. AN ESTIMATE, NOT A QUANTITY SURVEY This is a simplified educational tool for whole-house siding. Real jobs vary with the product and its exposure, panel lengths, corner and transition details, soffit and fascia returns, offcut reuse and how your supplier packages the material. Measure each elevation on site, allow for anything the perimeter method cannot see, and always confirm the final order with your supplier or installer before buying. This app is for general information and education only and is not professional construction advice. PRIVACY The app collects no personal data and works fully offline. Ads are served by Google AdMob, which may use an advertising identifier as described in Google's policies. Download Siding Calculator and get a quick, sensible picture of the squares and the trim your next siding job will take.