EngiRef
The terms you agree to by using EngiRef: what Premium buys, how refunds and cancellation work, and the limits of reference data.
These are the terms you accept by using EngiRef, the web edition. Read them with the Privacy page, which covers what happens to your data. If you do not accept them, stop using the app. They may be updated as the product changes; the updated date at the top of this page moves when they do, and continuing to use EngiRef after a change means you accept the revised terms.
Calculations, conversions, quiz results, exported sheets and reference content are provided as they are, with no warranty of any kind, express or implied. EngiRef does not guarantee that any value is complete, current or free of error, and it is not liable for loss arising from reliance on them. Check anything that matters against the source it came from before you act on it.
EngiRef Premium unlocks the printable reference sheets, the material comparison CSV and printed comparison sheet, custom formulas, and quiz rounds drawn from the disciplines you pick. Everything else stays free and unmetered: formula browsing, the unit converter, every reference table, the physical constants, the material property sheets, the full side-by-side comparison, today's replayable quiz round and your calculation history carry no time limit and no play count. Calculation history is held in your browser rather than on a server, so it keeps your most recent 500 calculations and can be exported as JSON at any time. Subscriptions (weekly or yearly) renew automatically until cancelled; lifetime is a one-time payment with no renewal.
Cancel a subscription at any time from the link in your receipt email, which stops the next renewal and leaves your access running to the end of the period you already paid for. Lifetime is a one-time payment, so there is nothing to cancel. Checkout and billing are handled by RevenueCat and Stripe under their own terms, and any money returned to you goes back to the original payment method.
Not happy with a purchase? Email [email protected] within 14 days of a first purchase, or within 7 days of a renewal, and we will refund it. Send the message from the email address you used at checkout, and include:
That is everything needed to find the purchase and process the refund. This policy does not limit any statutory rights you may have.
EngiRef stores all your data locally in this browser. There are no accounts and no server database, so Premium is recognised per browser rather than per person: use the access code on the Restore route to move it to another browser or device, and export your data as JSON from the Data route to take that with you. Clearing your browser storage without exporting first erases the data permanently, and there is no server-side copy to restore it from.
Formulas, materials data, reference tables, physical constants, conversions, and quiz content are provided for study and quick reference only - not as safety-critical engineering advice. Verify all values against current standards, codes, and manufacturer data before relying on them for design, professional, academic, or safety decisions. Nothing here replaces a licensed engineer, a current copy of the governing code, or a manufacturer's own datasheet.
Use EngiRef for your own study and work. Do not attempt to disrupt the service, scrape it at scale, resell or redistribute the reference content as your own, or work around the Premium gates rather than paying for them. Access may be withdrawn where these terms are broken. You are responsible for complying with the law that applies where you use the app.
EngiRef is an independent reference app for engineers and students. It is not affiliated with any standards body, manufacturer, professional association, or certifying authority, and it publishes no material on their behalf. There is no company office to visit and no call centre: one inbox handles everything, and it is read by the people who build the app.
Write to [email protected] for a billing or subscription problem, a privacy request, a correction to a reference value, or anything else about these pages. Include the receipt email address you paid with when the question is about a purchase, since that is the only thing that identifies an account.