How to measure a house for vinyl siding
Siding is measured by wall area, not floor area: walls are perimeter × height, each gable is a triangle, and windows and doors come off the total. One square of siding covers 100 sq ft of wall.
Net wall area = perimeter × height + gables − openings160 × 9 + 225 − 222 = 1,443 sq ft
The gable height is the rise from the eave to the peak: half the gable's width times the roof pitch ÷ 12. A 30-ft gable under a 6/12 roof rises 7.5 ft, so its triangle is ½ × 30 × 7.5 = 112.5 sq ft. Gable triangles add up quickly on steep roofs:
| Gable width | 4/12 | 6/12 | 8/12 | 10/12 | 12/12 |
|---|---|---|---|---|---|
| 24 ft | 48 | 72 | 96 | 120 | 144 |
| 28 ft | 65 | 98 | 131 | 163 | 196 |
| 32 ft | 85 | 128 | 171 | 213 | 256 |
| 36 ft | 108 | 162 | 216 | 270 | 324 |
| 40 ft | 133 | 200 | 267 | 333 | 400 |
What siding jobs cost in national data
Homeowners did about 2.3 million siding jobs in the two years to 2023, with a median cost of $5,000 and an average of $8,990, according to the Census Bureau's American Housing Survey.[1] The survey covers every siding material and job size, including partial repairs and owner-installed work, so it is a sense of scale, not a price for your house. On new homes, the builders' 2024 cost survey put the exterior wall finish at $24,450 on average, 5.7% of construction cost.[2]
| Part | Calculation | Area |
|---|---|---|
| Walls | 160 ft × 9 ft | 1,440 sq ft |
| Gables | 2 × ½ × 30 × 7.5 | 225 sq ft |
| Windows | 12 × 15 sq ft | −180 sq ft |
| Doors | 2 × 21 sq ft | −42 sq ft |
| Net wall area | 1,443 sq ft | |
| Order with 10% waste | 1,443 × 1.10 | 1,587 sq ft = 15.9 squares |
What a siding quote should spell out
- Area and unit. Squares or square feet of wall, and whether openings were deducted.
- Removal. Tearing off the old siding and disposal, or installing over it.
- Weather barrier and trim. House wrap, corners, J-channel, window and door trim, soffit and fascia.
- Repairs. A price per sheet or per foot for rotten sheathing found during removal.
Vinyl is one of the materials the builders' life-expectancy study lists as lasting for the life of the house, along with brick and fiber cement; the study calls its figures a general guideline only.[3]
Worked example
The default house is 50 × 30 ft, one story. Walls: 1,440 sq ft. Two gables at 6/12: 225 sq ft. Twelve 3 × 5 ft windows and two 21 sq ft doors: 222 sq ft. Net: 1,443 sq ft; with 10% waste, 1,587 sq ft or 15.9 squares. The cost is 1,587 × your installed price per square foot, plus removal and trim. The same house's roof is sized on the roof replacement cost calculator, the gutter installation cost calculator handles the eaves, and the window replacement cost calculator prices the openings if they are being replaced too.
Paying for new siding
New siding on the whole house is a substantial improvement in the IRS sense if it adds value or extends the home's useful life, so interest on home equity borrowing used for it can count as deductible home mortgage interest; money used for other things does not.[4] The CFPB's guide on home equity lists home improvements among common uses and warns that missed payments can lead to foreclosure.[5] Run the numbers on the home improvement loan calculator, or check your borrowing room with the HELOC LTV calculator.
Two stories?Use the full wall height from foundation to eave, about twice a one-story wall, and count every gable end. Bay windows and dormers add wall that a simple perimeter misses.
Frequently asked questions
How much siding do I need for a 2,000 sq ft house?
Floor area does not decide it; wall area does. A two-story 25 × 40 ft house (2,000 sq ft of floor) with 18-ft walls, two 6/12 gables, 20 windows and 2 doors has about 2,154 sq ft of wall to cover, or 23.7 squares with 10% waste.
Do you subtract windows and doors when measuring for siding?
Yes, for the area you pay to cover, but keep a waste allowance: siding around openings is cut, and the offcuts are rarely reusable.
How long does vinyl siding last?
The NAHB life-expectancy study lists vinyl siding as lasting the lifetime of the house, as a general guideline.[3] Trim, caulk and the weather barrier behind it need attention sooner.
What does siding cost on average?
In the 2023 American Housing Survey, homeowners' siding jobs had a median cost of $5,000 and an average of $8,990, across all materials and sizes.[1]
Sources
- American Housing Survey 2023, Table C-16-OO: Home Improvement Costs, Owner-Occupied Units (Table Creator estimates)
- Cost of Constructing a Home, 2024 (Special Study)
- Study of Life Expectancy of Home Components
- Publication 936 (2025), Home Mortgage Interest Deduction
- Using home equity to meet financial needs (Older Americans Housing Guide)