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    Terms of Use

    Last reviewed 2026-10-29

    1. What this is

    ZorvLabs ("the site") provides Free, browser-based calculators for finance and engineering. By using the site you agree to these terms. If you do not agree, please do not use the site.

    2. Free service, and paid plans

    The core calculator experience requires no registration and is provided free of charge without display advertising. Optional Pro and Ultra plans add workflow features — reports, saved revisions, composition, exports and heavier analysis — on top of a calculation that never changes with the plan.

    When checkout is open in your region, paid plans are sold as subscriptions through Paddle, acting as merchant of record. The terms that matter:

    • Billing cycle. Monthly or annual, as shown at checkout. Subscriptions renew automatically at the end of each cycle until cancelled.
    • Cancellation. Cancel any time from the customer portal linked on your account page. Cancellation stops future renewals; the paid period you already covered stays active.
    • Trial. Where a free trial is offered, it runs for the length stated at checkout and converts to a paid subscription unless cancelled before it ends.
    • Refunds. A money-back guarantee is stated on the pricing page; refund requests inside it are handled by Paddle at paddle.net.
    • Prices and tax. Prices are shown before checkout completes; applicable tax is calculated by Paddle and shown there. We may change plan prices with notice on the pricing page; your price for an active subscription does not change mid-cycle.

    While billing is not connected in a deployment, no charge can occur and the paid capabilities are described as packaging only.

    3. No professional advice

    All results are informational estimates produced by the formulas described on each calculator page. They are not financial, investment, tax, legal or engineering advice, and must not be used as the sole basis for any decision. See the full disclaimer.

    4. Acceptable use

    • Don't attempt to disrupt, overload or reverse-engineer the service beyond what the published formulas describe.
    • Don't scrape the site in ways that violate robots.txt or impose unreasonable load.
    • Don't present the site's output as your own professional work product or redistribute the site as if it were yours.

    5. Intellectual property

    The site's code, design and editorial text are the property of the site's authors. The underlying mathematical formulas (annuity factors, Black–Scholes, beam theory, etc.) are standard published methods and are not claimed as proprietary; references are given on each page.

    6. Warranty and liability

    The site is provided "as is" and "as available", without warranties of any kind, express or implied, including accuracy, fitness for a particular purpose and non-infringement. To the maximum extent permitted by law, the authors are not liable for any loss arising from use of, or inability to use, the site or its results — including financial loss, missed deadlines or structural decisions based on calculator output.

    7. Availability and changes

    The site may change, suspend or remove any calculator at any time. We may update these terms; the "last reviewed" date above will change when we do, and continued use after a change constitutes acceptance.

    8. Contact

    Questions about these terms: see the contact page.