About Us

Home Addition Estimator is an independent cost-planning site. It exists to give homeowners a clear, checkable starting figure before they talk to contractors — not to sell building work.

Every estimate on this site uses the same published method: a per-square-foot rate by addition type and finish, plus foundation and feature allowances, adjusted by a state index. The method is shown on the homepage and on every calculator page, so any result can be recomputed by hand. No estimate is gated behind contact details, and the site collects no project information from the calculators.

The cost data is presented as 2026 planning ranges. It is not a quote, a valuation, or professional advice for a specific property. Building costs vary with site, specification, and local market, so itemised bids from licensed local contractors remain essential. The guides on this site explain how to compare those bids, what to check before building, and how to plan a realistic timeline.

Questions about the site can be sent through the contact page. See also the frequently asked questions.