Terms of Use & Disclaimer

Agreement

By using TimberMath (the "Site") you agree to these Terms of Use and to the Disclaimer below. If you do not agree, please do not use the Site. These terms may be updated from time to time; the "last updated" date at the top of this page reflects the current version.

What this Site is (and isn't)

TimberMath is an independent data project offering free woodworking calculators and reference tables built on published wood science. It is an educational and planning reference — not professional engineering, structural, architectural, construction, or safety advice, and not a substitute for the judgment of a qualified professional.

The Site is not affiliated with, endorsed by, or sponsored by the USDA, any lumber supplier, or any tool manufacturer.

Estimates, not guarantees

Every number on the Site — board-foot volumes, seasonal wood movement, weights, Janka hardness, density, shrinkage — is a reference estimate. Wood is a natural, variable material: real boards differ from tabulated averages with species, grain orientation, density, growing conditions, and drying history. Calculator results spread published shrinkage across a modeled fiber-saturation point and are approximations, most reliable in the ordinary interior moisture range and least reliable at the extremes.

Treat all outputs as planning figures. Verify anything critical against your own stock, and consult a qualified professional (engineer, architect, or experienced tradesperson) for load-bearing, structural, or safety-critical work. You are responsible for how you use the information.

Accuracy and warranty disclaimer

The Site and everything on it are provided "as is" and "as available," without warranties of any kind, whether express or implied — including, to the fullest extent permitted by law, any implied warranties of accuracy, merchantability, fitness for a particular purpose, and non-infringement.

Considerable care goes into transcribing every value from its cited source and documenting each formula on the page that uses it. Even so, we do not warrant that the Site is accurate, complete, current, or error-free, or that it will be uninterrupted or available. If you find a figure that disagrees with the source, please report it (see Contact) — corrections are the fastest way to improve the Site for everyone.

Limitation of liability

To the fullest extent permitted by law, TimberMath and those who operate it will not be liable for any loss or damage — including wasted material, project costs, or any direct, indirect, incidental, or consequential damages — arising from your use of, or reliance on, the Site or its calculations. You use the Site at your own risk.

Data sources and attribution

The underlying wood-property data is drawn from the USDA Forest Products Laboratory Wood Handbook — Wood as an Engineering Material (FPL-GTR-282, 2021), a work of the U.S. Government that is in the public domain. The exact tables used and the basis of each value are documented on the methodology page.

The public-domain status applies to the underlying government data. This Site's original text, layout, presentation, and code are not public domain and remain the property of the project; please do not republish them as your own. You are welcome to use the underlying USDA data — it is public domain — and to cite this Site.

Acceptable use

You may use the Site for personal and professional reference. You agree not to:

• Scrape, crawl, or hammer the Site in a way that degrades it or disrupts service for others.
• Misrepresent the Site or its data as an official USDA publication, or imply endorsement that does not exist.
• Use the Site for any unlawful purpose or in violation of these terms.
• Attempt to interfere with the Site's security or normal operation.

External links

The Site links to third-party resources — primary sources such as the USDA Forest Products Laboratory, and other references — purely for convenience. We do not control those sites, are not responsible for their content or practices, and their inclusion is not an endorsement.

Advertising

The Site currently displays no advertising. It may add third-party ads (such as Google AdSense) in the future to cover costs. If it does, advertising will never change a published value, a chart ranking, or a recommendation, and the handling of any data collected by ad partners is described in the privacy policy.

Changes to these terms

These terms may change as the Site evolves. Continued use after a change means you accept the revised terms; the "last updated" date above always reflects the current version.

Contact

Questions about these terms, corrections to any published value, or reuse questions can be sent to [email protected]. Correction reports are prioritized.