Siding Calculator
Estimate how much siding your house needs - enter the perimeter, wall height and gable ends to get the squares of siding after openings and waste, plus a material cost estimate.
United States — national average · 2026 prices
Material only unless stated as installed. Excludes tax, permits and local labour. Verify with local suppliers — see how we calculate.
How this calculator works
Every figure above comes from the formula below, applied to the assumptions listed. Nothing is looked up from a hidden table — you can reproduce the result by hand.
Formula
wall area = perimeter × wall height
gable area = gables × ½ × gable width × gable rise
net = (wall + gable area) × (1 − openings% ÷ 100)
order = net × (1 + waste ÷ 100) · squares = order ÷ 100
Assumptions & limits
- A "square" is 100 sq ft of siding, the unit the material is sold in.
- Gables are treated as triangles (half of width × rise). Hip roofs have no gables — set the count to zero.
- Openings default to a 10% deduction. For a tight bid, measure the real windows and doors instead of using the percentage.
- Default waste is 10%; complex walls with many corners and penetrations need more.
- Material price defaults to $3 per sq ft, mid-grade vinyl (real range roughly $2–$4.50). Fiber cement and engineered wood run higher. Accessories — starter strip, J-channel, corner posts — are estimated at 20% of the siding cost.
- Labor is excluded. Installed vinyl commonly runs $4–$8 per sq ft; installation standards are the manufacturer’s and the VSI certification program’s territory.
Worked example
A house with 140 ft perimeter, 9 ft walls, two 30 ft gables rising 8 ft, 10% openings, 10% waste, $3/sq ft vinyl
- Wall area = 140 × 9 = 1,260 sq ft
- Gable area = 2 × ½ × 30 × 8 = 240 sq ft → gross 1,500 sq ft
- After openings = 1,500 × 0.90 = 1,350 · with waste = 1,485 sq ft
- Squares = 1,485 ÷ 100 = 14.9
Result:About 14.9 squares — roughly $4,800 to $6,400 in material and accessories.
Built and maintained by Christoph Ballmer, Honeygoat GmbH
Method and constants last checked against the calculator code on August 25, 2026. Independent trade review is not yet in place for this calculator — see how we handle review.
Read the site-wide calculation methodology · estimate vs. quote and safety limits
How to calculate siding
Siding is estimated from the wall surface, and the wall surface comes from three measurements you can take with a tape from the ground: the house perimeter, the wall height to the eaves, and the gable ends. Each gable is a triangle — half of its width times its rise. Subtract the windows and doors, add waste, and divide by 100, because siding is sold in squares of 100 square feet.
squares = (perimeter × height + gables × ½ × width × rise) × (1 − openings%) × (1 + waste%) ÷ 100
The openings deduction defaults to 10%, which fits a typical house. For a tight bid, measure the real window and door areas instead — a sunroom wall of glass breaks any percentage rule.
What siding costs per square
| Material | Material $/sq ft (2026) | Installed $/sq ft |
|---|---|---|
| Vinyl (mid-grade) | $2.00–$4.50 | $4–$8 |
| Insulated vinyl | $4.00–$7.00 | $6–$12 |
| Fiber cement | $2.50–$6.00 | $6–$13 |
| Engineered wood | $3.00–$6.00 | $5–$12 |
The calculator prices material and accessories only — starter strip, J-channel and corner posts reliably add about 20% to the siding itself, and forgetting them is the classic first-order mistake. Labor is quoted locally; vinyl installation standards and installer certification run through the VSI program.
Why floor area cannot answer the question
"How much siding for a 2,000 sq ft house" has no single answer, because siding covers walls, not floors. A single-story ranch spreads its 2,000 sq ft wide — long perimeter, low walls — while a two-story colonial stacks it: shorter perimeter, double the wall height. The two can differ by eight squares or more. Measure the actual perimeter and heights; the calculator does the rest.
Related planning
Re-siding often happens alongside other envelope work: the roof replacement cost calculator budgets the roof above it, and if the old siding comes off, the paint calculator covers the trim-and-touch-up pass that follows. For the sheathing under the siding, see the plywood calculator. Pricing fiber cement rather than vinyl? The James Hardie siding calculator opens at fiber-cement prices and the 12% waste those fixed-length planks actually carry.
Figures are planning estimates for material quantities and 2026 national price ranges — actual coverage varies by profile and exposure, so confirm with your supplier before ordering.
Frequently asked questions
How do you calculate how much siding you need?
Multiply the house perimeter by the wall height, add the gable triangles (half of width x rise for each), subtract about 10% for windows and doors, then add 10% waste. Divide by 100 for squares - the unit siding is sold in. A 140 ft perimeter with 9 ft walls and two 30 x 8 ft gables works out to about 14.9 squares. The calculator above runs exactly this.
How much does it cost to side a 1,500 sq ft house?
A typical single-story 1,500 sq ft house has roughly 1,300-1,700 sq ft of wall surface once gables are counted and openings subtracted. In mid-grade vinyl at $2-$4 per sq ft for material, that is about $3,000-$6,500 in siding and accessories; professionally installed, vinyl commonly lands around $6,000-$12,000. Fiber cement and engineered wood run meaningfully higher.
How much is 1,000 square feet of siding?
In material terms, 1,000 sq ft is 10 squares. Mid-grade vinyl material runs about $200-$400 per square, so $2,000-$4,000 plus roughly 20% for starter strip, J-channel and corner posts. Installed, plan on about $4,000-$8,000 for vinyl - and more for premium profiles or insulated panels.
How much siding does a 2,000 sq ft house need?
Floor area alone cannot answer this - the wall area depends on the shape. A single-story 2,000 sq ft house might have a 180 ft perimeter and 9 ft walls (about 16-18 squares with gables), while a two-story house with a 130 ft perimeter and 18 ft of wall carries 23-26 squares. Measure the perimeter and heights and let the calculator above do the rest.