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Siding is priced by the square foot of wall it covers. The Siding Cost Calculator measures the wall the way a contractor does — perimeter × wall height, plus each gable triangle (width² × pitch ÷ 48), minus a typical 15 sq ft per window and 20 sq ft per door — and multiplies it by an installed price. The default prices come from Zonda's 2025 Cost vs. Value Report (Journal of Light Construction), which puts replacing 1,250 sq ft of existing siding, trim included, at a national average of $17,950 in vinyl and $21,485 in factory-primed and painted fiber cement: $14.36 and $17.19 per square foot. Fiber cement costs about 20% more. Prices swing widely by region and house, so a local quote per square foot can replace the national figure. A 40 × 30 ft house with 9 ft walls, two 6/12 gables, 10 windows and 2 doors has 1,295 sq ft of wall: about $18,596 in vinyl or $22,258 in fiber cement.
Zonda’s 2025 Cost vs. Value Report (Journal of Light Construction, jlconline.com/cost-vs-value/2025) prices replacing 1,250 sq ft of existing siding, trim included, at a national average of $17,950 in vinyl and $21,485 in factory-primed and painted fiber cement — about $14.36 and $17.19 per square foot installed. At resale the report puts vinyl at $17,313 (96.5% recouped) and fiber cement at $24,420 (113.7%). Multiply your wall area — perimeter × height, plus gables, less windows and doors — by the price per square foot.
| Wall area | Vinyl siding | Fiber cement siding |
|---|---|---|
| 800 sq ft | $11,488 | $13,750 |
| 1,000 sq ft | $14,360 | $17,188 |
| 1,250 sq ft | $17,950 | $21,485 |
| 1,500 sq ft | $21,540 | $25,782 |
| 1,750 sq ft | $25,130 | $30,079 |
| 2,000 sq ft | $28,720 | $34,376 |
| 2,500 sq ft | $35,900 | $42,970 |
| 3,000 sq ft | $43,080 | $51,564 |
Zonda's 2025 Cost vs. Value Report (Journal of Light Construction) puts the national average for replacing 1,250 sq ft of existing siding at $17,950 for vinyl and $21,485 for factory-primed and painted fiber cement, trim included — about $14.36 and $17.19 per square foot installed. A 40 × 30 ft house with 9 ft walls and two gables has 1,295 sq ft: about $18,600 in vinyl or $22,300 in fiber cement.
About $14.36 per sq ft on the 2025 Cost vs. Value national average ($17,950 ÷ 1,250 sq ft) for replacing existing siding with new vinyl and factory trim at openings and corners. Prices vary widely by region and house complexity, so use the calculator's price box to run a local quote.
Yes — about 20% more on the 2025 Cost vs. Value national averages: $21,485 against $17,950 for the same 1,250 sq ft job, or roughly $2.83 more per square foot. It also returned more at resale in that report: $24,420 (113.7% of cost) against $17,313 (96.5%) for vinyl.
Multiply the perimeter by the wall height, add each gable triangle (width² × pitch ÷ 48 — a 30 ft gable at 6/12 is 112.5 sq ft) and subtract windows and doors. Contractors price by the square (100 sq ft); add about 10% for waste when ordering material yourself.
Rotten sheathing found during tear-off, a new weather-resistive barrier (IRC R703.2), extra corners and gables, two- and three-storey access, and trim around many windows. Ask each contractor to price the same scope so the quotes compare.
Buying the material yourself? The siding calculator counts squares, vinyl cartons and Hardie planks.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.