How much siding do I need? Calculate squares, panels, trim pieces, and costs for vinyl, fiber cement, wood, metal, and engineered wood siding. Accounts for doors, windows, and gable areas.
House Perimeter (ft)
Wall Height (ft)
Doors
Windows
Gable Area (sq ft)
Siding Type
Waste Allowance
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Enter your house dimensions
Last updated March 31, 2026 by our expert review team
Material cost only. Installation adds $2-$6/sq ft depending on type and region.
Hawkin
Certified Cost & Estimating Professional
AACE-certified estimator working with 20+ insulation companies including the two largest franchises in America.
See full profileEhsan Ghazanfari
Licensed Structural Engineer
FISE-certified structural engineer with 11+ years designing bridges, retaining walls, and foundations. MSc from Aalto University.
See full profileUpdated March 2026
How we verify our calculatorsFor a modern farmhouse look, consider board and batten siding. It pairs well with horizontal lap siding as an accent on gable ends.
Always install house wrap (like Tyvek) before siding. It is your second line of defense against bulk water and prevents moisture from reaching the sheathing.
Leave a 1/4-inch gap at all butt joints for vinyl siding expansion. Vinyl expands and contracts significantly with temperature. Nailing too tight causes buckling.
Wood siding requires painting or staining every 5 to 7 years. Use our paint calculator to estimate how much exterior paint you need.
Fiber cement siding should be pre-primed and painted before installation. Factory-primed boards with a field-applied topcoat last 15+ years between repaints.
Overlap each course by at least 1.25 inches (vinyl) or per manufacturer specs. Insufficient overlap allows wind-driven rain behind the siding.
Start your first course perfectly level using a chalk line. Every subsequent course references the first, so errors compound quickly up the wall.
Our siding calculator starts with the gross wall area: house perimeter multiplied by wall height, plus any gable area you enter separately. Gable ends are triangular sections above the eave line that many homeowners forget to include, which leads to ordering 10-15% too little material. The calculator then deducts standard openings: 21 sq ft per door (3 ft x 7 ft) and 15 sq ft per window (3 ft x 5 ft average).
After subtracting openings from the gross area, the waste factor is applied to the net area. For simple rectangular homes, 10% waste is standard. Homes with many corners, dormers, or complex rooflines should use 15-20%. The result is expressed in "squares," the industry standard unit where 1 square = 100 sq ft. Ordering siding by the square simplifies purchasing because manufacturers package material in square increments.
The calculator also estimates trim accessories. J-channel runs around every window and door opening (calculated from the perimeter of each opening with 10% waste). Corner posts cover inside and outside corners at each wall intersection. Starter strip runs along the bottom of all walls to lock the first course in place. These trim pieces are often overlooked but can add $200-$500 to a project if you have to make a second trip to the supply house.
Formula
Gross Area = Perimeter x Wall Height + Gable Area
Net Area = Gross Area - (Doors x 21) - (Windows x 15)
Squares = Ceiling(Net Area x (1 + Waste%) / 100)
How much does siding cost for a 1,500 sq ft house?
Material costs range from $3,000-$7,500 for vinyl to $7,500-$15,000 for fiber cement. Add $3,000-$9,000 for professional installation. Total project cost for an average home runs $6,000-$22,000 depending on siding type.
What is a 'square' of siding?
One square covers 100 square feet of wall area. It is the standard ordering unit for siding, roofing, and other exterior cladding. A typical home needs 15-25 squares of siding.
Is vinyl or fiber cement siding better?
Vinyl costs less upfront ($2-$5/sq ft) and never needs painting, but dents easily and fades over 15-20 years. Fiber cement ($5-$10/sq ft) resists fire, insects, and rot, holds paint longer, and lasts 30-50 years.
How long does each siding type last?
Vinyl: 20-40 years. Fiber cement: 30-50 years. Wood: 20-40 years (with maintenance). Metal: 40-60 years. Engineered wood: 20-30 years. All lifespans depend on climate, maintenance, and installation quality.
Can I install new siding over existing siding?
Yes, in many cases. Vinyl can go over old vinyl or wood. However, adding layers traps moisture, hides rot, adds weight, and may void warranties. Best practice is to remove old siding, inspect sheathing, and install fresh.
What is J-channel and do I need it?
J-channel is a trim piece that frames windows, doors, and rooflines. It hides cut siding edges and directs water away from openings. Every siding installation needs J-channel. Budget 16-17 linear feet per opening.
Should I add insulation behind siding?
Foam-backed siding or continuous rigid foam insulation (1/2 to 1 inch) under siding adds R-2.5 to R-6 and reduces thermal bridging. It is especially valuable in older homes with 2x4 walls and minimal cavity insulation.
Which siding has the best resale value?
Fiber cement siding recoups 70-80% of its cost at resale according to Remodeling Magazine's Cost vs. Value report. Vinyl returns 65-70%. Quality installation matters more than material choice for appraisal impact.
Small Ranch (1,200 sq ft)
120 ft perimeter, 9 ft walls, 60 sq ft gableRanch homes are the easiest DIY siding project. One story means no scaffolding, just a sturdy ladder and a helper for long panels.
Two-Story Colonial (2,400 sq ft)
160 ft perimeter, 18 ft walls, 200 sq ft gableTwo-story homes require scaffolding and often a second color or accent material on the upper floor. Budget an extra 5% waste for the added complexity.
Large Home (3,500 sq ft)
200 ft perimeter, 20 ft walls, 300 sq ft gableLarge homes often mix siding types: lap siding on the body with board and batten or shake accents on gable ends. Order each material separately.
Detached Garage (24 x 24 ft)
96 ft perimeter, 10 ft walls, 48 sq ft gableMatch your garage siding to the house for curb appeal. Most suppliers can color-match vinyl or fiber cement to your existing siding within one shade.
Not accounting for gable areas
Gable ends can add 100-300 sq ft to a typical home. Measure the triangle (base x height / 2) for each gable and add it to your wall area before calculating.
Forgetting J-channel and trim pieces
Every window, door, and roofline junction needs J-channel. Corner posts, starter strip, and undersill trim add up fast. Budget 10-15% of your siding cost for trim alone.
Installing over rotted sheathing
New siding over damaged sheathing traps moisture and accelerates structural decay. Always remove old siding, replace any soft or water-stained OSB/plywood, then re-side.
Using wrong nail length or placement
Vinyl siding nails should penetrate 3/4 inch into studs. Drive nails into the center of the nailing slot and leave 1/32 inch gap. Over-driven nails prevent thermal movement and cause buckling.
Skipping house wrap under siding
House wrap (Tyvek, Typar) is not optional. It is your water-resistive barrier. Without it, wind-driven rain reaches the sheathing and causes mold, rot, and insulation damage within a few years.
Important Disclaimer
These estimates are for planning purposes only. Actual costs vary by location, material availability, and project complexity. Always get at least 3 local quotes. This calculator does not replace professional advice.