Calculate Exterior
Materials Instantly
Skip the spreadsheets and guesswork. Get precise siding square takeoffs, gutter slope elevations, downspout counts, and soffit ventilation modeled for real job sites.
Featured Exterior Calculators
Siding Calculator
Calculate total siding squares, cartons, panels, and trim accessories for rectangular walls and gables with opening deductions.
Gutter Slope Calculator
Determine calculated geometric fall in fractional inches, slope percentage, and intermediate chalk line marks for single or center-split horizontal runs.
Vinyl Siding Calculator
Determine vinyl siding cartons, specific profile exposures (Double 4", 4.5", 5", Single 7"), J-channel, and corner posts.
Downspout Calculator
Calculate the required number of downspouts, profile sizing (2x3" vs 3x4"), spacing analysis, and wall offset elbows.
Hardie Plank Siding Calculator
Calculate James Hardie fiber cement plank counts, exposure reveals, joint flashing tabs, blind nails, and corner boards.
Soffit Vent Calculator
Calculate required Net Free Vent Area (NFVA) for attic ventilation using the IRC 1:150 baseline or 1:300 exception, with balanced intake and exhaust sizing.
Dedicated Siding, Gutter, Downspout & Roof Edge Calculators
Siding Cost & Labor Calculator
Estimate total material costs, tear-off expenses, and contractor installation labor rates across vinyl, fiber cement, and wood siding.
Siding Waste Factor Estimator
Calculate waste allowances for complex gable peaks, dormers, window cutouts, and diagonal architectural walls.
Gutter Parts & Hardware Calculator
Estimate seamless gutter sections, hidden screw hangers, inside/outside miter corners, end caps, and sealant tubes.
Gutter Sizing Calculator
Size gutter trough width and profile based on roof catchment area, pitch factor, and local 1-hour design rainfall intensity.
Gutter Water Volume & Flow Rate
Calculate peak storm runoff flow in GPM, trough storage capacity, and Manning equation velocity for residential eaves.
Soffit Panel & Channel Calculator
Calculate 12-ft soffit panel yields, F-channel perimeter tracks, and J-channel trim for closed or open rafter overhangs.
Fascia Board & Wrap Calculator
Determine 1x6/1x8 lumber lengths, aluminum fascia trim coil footage, and overlap waste for complete roof edge protection.
Why Field Pros Use ExteriorCalc
Engineered to eliminate costly siding shortages, standing gutter water, and job site guesswork.
Built-in Waste Geometry
Real jobs aren't flat planes. We calculate geometric safety buffers for 45° angle cuts, gable rakes, opening deductions, and lap overlaps.
Standard Trade Units
Takeoffs in exact commercial packages: 100 sq ft squares, 2.00 sq cartons, 10-ft gutter lengths, and IRC net free vent square inches.
Standards-Based Formulas
Developed by Alish Gautam. Calculation models formulated from published building codes (IRC) and trade standards (SMACNA, VSI).
Fast & Distraction-Free
No sign-up, no popups, and no newsletter modals blocking your screen on the job site or at the supply counter.
Calculator Guides & Field Notes
How to Calculate How Much Siding You Need (Step-by-Step)
A complete contractor-grade walkthrough on measuring rectangular walls, gable peaks, opening deductions, and ordering squares.
How Many Squares of Siding Do I Need? Siding Squares Explained
Learn what a siding square is, why construction uses squares instead of individual panels, and how to calculate exact carton requirements.
How to Calculate Gutter Slope & Pitch (The 1/4" Per 10-Foot Rule)
Detailed instructions on measuring horizontal run, calculating total elevation fall in fractional inches, and snapping chalk lines along eaves.