Siding tools and calculators

To measure, take each wall's height times its width and add them up, then add gable triangles (half base times height) and subtract large openings. Divide by 100 to get squares. Do this before you call anyone. Having your own number is the simplest defense against an inflated measurement.

Then apply a rate. Cost guides publish installed rates by material — This Old House lists vinyl at $6.13, fiber cement at $9.00, and cedar at $11.70 per square foot. Add tear-off (about $1,000 to $2,500 on a vinyl job, per Fixr), trim, and permits ($150 to $1,500 per Fixr) as separate lines rather than assuming they're baked in.

What no calculator can price: rotten sheathing, difficult access, multi-story staging, custom trim, and local labor rates. Those are exactly the items that separate a $14,000 job from a $24,000 one on the same house. Treat calculator output as a sanity check on quotes, not a target for negotiation.

How to choose

Measure walls, not floors

Height times width per elevation, plus gables, minus large openings, divided by 100 for squares.

Use installed rates, not material prices

Material-only prices understate a job by roughly half once labor is included.

Add the separate lines

Tear-off and disposal, trim and soffit, permits, and a rot allowance. Calculators usually omit all four.

Build a range, not a point

Run the low and high rates for your material. If every quote lands outside that band, ask why.

Don't negotiate against a calculator

A number from a website is not evidence about your house. Use quote-to-quote comparison on an identical scope instead.