What this site is
Square Footage Calculator provides a free web-based area calculator and educational content about measurement, materials, and construction. The site is offered as-is, without any guarantee that the calculator or content will be available, error-free, or suitable for any specific purpose.
Accuracy and limitations
We work hard to keep the calculator's formulas correct and the content factual. Even so, mistakes are possible, and the calculator does not know the specifics of your project. You are responsible for double-checking any measurement that affects a material order, building permit, real estate transaction, or other significant decision.
Square footage requirements vary by jurisdiction, by lender, by appraiser, and by trade. The numbers from this calculator are not certified for any official purpose. Always confirm with a licensed professional when accuracy matters legally or financially.
No professional advice
Nothing on this site constitutes professional construction, engineering, real estate, legal, or financial advice. Our content is intended to help readers understand measurement concepts and plan their projects. For specific guidance on your situation, consult an appropriate licensed professional.
Where the figures come from
Two kinds of number appear on this site and they carry different weight. Geometry and unit conversions are exact definitions: an acre is 43,560 square feet, a square foot is 0.09290304 square metres, and the area formulas are standard mathematics that does not vary by region or year. Those figures are verified against an automated test suite that runs against the calculation library.
Everything else is an estimate. Material coverage rates, waste allowances and cost ranges reflect common industry practice and published pricing at the time of writing. Waste percentages are installer convention rather than code. Cost figures move with region, season and job complexity, and they are labelled as planning ranges wherever they appear. Treat them as a way to sanity-check a quote, never as a substitute for one.
Verify before you commit money
The output of a calculator is only as good as the measurements you feed it, and we have no way to check those. Before placing a material order, re-measure from a different starting point and confirm the two results agree. Before relying on a figure in a property transaction, appraisal, permit application or dispute, engage a licensed appraiser or surveyor — a professional measurement carries accountability that a free tool cannot.
Manufacturer specifications always take precedence over the coverage rates used here. If a carton states its own coverage, or a paint tin states its own spread rate, use that number instead of ours.
Acceptable use
You may use the calculator for any lawful personal, commercial, or educational purpose. You may share links to pages on this site freely.
You may not scrape large portions of the content for republication without permission, attempt to overload the servers, or use automated tools to misrepresent the source of any content.
Liability
To the fullest extent permitted by law, we are not liable for any damages arising from your use of the site, including (without limitation) project costs, material orders, real estate transactions, or business decisions made based on the calculator's output. Use the site at your own risk.
Changes
We may update these terms at any time. Continued use of the site after a change means you accept the new terms. Significant changes will be noted at the top of this page.