Terms of Service

Welcome to gutter-calculator.com (“the site”). By accessing or using the site — including the gutter size & downspout calculator, the accessory & fastening BOM, the hydraulic check, the shopping list, and the guide library — you agree to be bound by these Terms of Service and the Privacy Policy. If you do not agree with any part of these terms, please stop using the site.

You must be at least 13 years old to use the site. There is no registration, subscription, or account of any kind — acceptance happens simply by using the tools.

Gutter Calculator operates gutter-calculator.com, an independent publisher of free gutter-sizing calculators and drainage guides. We are not a gutter manufacturer, distributor, or installation contractor; we sell no products, take no orders, and receive no payment from any supplier whose parts appear in a shopping list. The site is funded by clearly separated advertising.

Because we sell nothing, nothing on the site is a product listing, a price quote, or an offer to contract — including the cost estimates the calculators produce from the prices you enter.

The service consists of free, browser-based tools and reading material:

• Gutter Size & Downspout Calculator — profile, downspout layout, and footage from roof geometry and design rainfall
• Accessory & Fastening BOM — elbows, hangers, straps, and miters with climate-zone spacing
• Hydraulic Check — storm-flow verification against cross-section and open area
• Checkable Shopping List — purchase-ready quantities with waste factor and PDF export
• Guides and reference tables — rainfall intensity, capacity data, and installation practice

The service is provided free of charge, as-is, and without any commitment to availability. Features may be added, changed, or retired at any time. There is no paid tier — no feature of the site is withheld behind a payment, now or later.

Every result is computed from the inputs you provide — the roof footprint, pitch, run lengths, rainfall, and prices. The calculators apply published formulas and capacity tables exactly; they cannot check that the inputs describe the roof you actually have. A tool fed a guessed footprint or a borrowed rainfall value produces an exact answer to the wrong question.

We reserve the right to suspend access for conduct that threatens the site’s availability or integrity — and only for that reason.

The site is a small, independently operated service. Keep your use within the spirit of a public workshop: personal, professional, and educational use is welcome and encouraged — including using results in customer-facing estimates, provided you stand behind them as your own work.

What is not acceptable is anything that degrades the site for everyone else: automated scraping at scale, load testing without permission, attempts to compromise the hosting, or republishing the tools wholesale as someone else’s product. Brief quotations of the guides with a link back are fine; wholesale copying is not.

Nothing on gutter-calculator.com constitutes professional engineering, contracting, or legal advice, nor a substitute for the judgment of a licensed roofing or gutter contractor, a structural engineer, or your local building department. The calculators produce planning estimates from published formulas; they do not evaluate your fascia, your exposure, your soil, or your jurisdiction’s amendments to the model codes.

Decisions about drainage design, structural attachment, discharge locations, and code compliance remain professional decisions. For any work governed by a permit or a specification, consult the current edition of the applicable standard and the authority having jurisdiction — and treat the calculator’s output as the strong hypothesis that the site verifies, not a stamp that replaces verification.

The calculators are built for planning and learning: sizing a system before requesting quotes, comparing bids against a defensible parts list, sanity-checking a supplier’s takeoff, and understanding how rainfall, pitch, and run geometry move the numbers.

They are not built — and not warranted — as the basis for a permit submission, a stamped design, or a guarantee against every storm. Roofline conditions the tools cannot see (concentrating valleys, clogged outlets, undersized discharge paths, storm intensities beyond the design value) are precisely the risks a verification step and a qualified installer exist for. See the full disclaimer for the complete picture.

The site displays advertising and may reference third-party resources — weather services, standards bodies, manufacturer documentation. We do not control third-party content and are not responsible for its accuracy or availability; links are provided for convenience, not endorsement.

Advertisements are clearly separated from tool output — never inside a results panel, never styled to look like a calculation, and never presented as a recommendation from the calculator. Advertising partners operate under their own privacy policies; see the Privacy Policy for details on what is and is not collected.

The site’s text, guides, calculators, diagrams, code, and visual design are the property of Gutter Calculator and are protected by copyright and other laws. You may use the tools freely and quote the guides briefly with attribution and a link; you may not republish, resell, or rebrand the site’s content or embed the calculators as your own product without written permission.

The underlying sizing mathematics — effective area, pitch correction, capacity ratios — is published engineering practice and belongs to no one. All third-party names, standards (IPC, IRC, FBC, NOAA, SMACNA), and trademarks mentioned on the site are the property of their respective owners and are referenced for identification and educational purposes only; no affiliation, sponsorship, or endorsement is claimed or implied.

The site and all content, tools, and results are provided “as is” and “as available” without warranties of any kind, express or implied — including fitness for a particular purpose, accuracy, availability, or non-infringement. We do not warrant that the calculators will be uninterrupted or error-free, that a computed size will clear every storm, or that a shopping list will match every supplier’s catalog.

To the maximum extent permitted by law, this disclaimer applies to every use of the site, whether you are a homeowner planning a purchase, a contractor preparing a bid, or an inspector forming an opinion.

To the maximum extent permitted by law, Gutter Calculator and its operators will not be liable for any indirect, incidental, special, consequential, or punitive damages arising from your use of — or inability to use — the site. This includes, without limitation: water damage to foundations, basements, siding, or landscaping; overflow attributed to undersized or clogged gutters; fascia or structural damage; ice or wind failures; injuries from ladder or roof work; failed inspections; costs differing from estimates; and losses arising from reliance on calculator output without verification.

Where liability cannot be excluded, it is limited to the amount you paid to use the site — which, because the site is free, means zero. Nothing in these terms excludes liability that cannot be excluded under applicable law.

You agree to indemnify and hold harmless Gutter Calculator and its operators from claims, damages, and expenses (including reasonable legal fees) arising from your misuse of the site, your violation of these terms, or your publication or use of calculator output in a manner these terms do not authorize — for example, presenting a planning estimate as a code-compliance design.

The calculators run entirely in your browser: roof measurements, rainfall values, and results are never transmitted to or stored on our servers. What little the site does process — server logs, aggregate analytics, local storage preferences — is described in the Privacy Policy, which forms part of these terms.

We may update these terms as the toolset evolves — for example, if new calculators or export features are added. The current version is always published on this page with a dated revision note, and material changes are described in plain language. Continued use of the site after a change constitutes acceptance of the updated terms; if a change troubles you, stop by the contact page and tell us why — the answer may be another revision.

These terms are governed by the laws of the jurisdiction in which the site operator is established, without regard to conflict-of-law principles. Because the service is free and provided as-is, disputes will in the first instance be addressed informally — write to us, describe the issue, and we will work with you toward a fair resolution before any formal process begins.