Privacy policy

Last updated 7 October 2026. This explains what Slide Rule knows about you and what it does with it. Slide Rule is run by Jesse Delahunty Dunning (ABN 76 715 112 597), in Australia.

In short

• Without an account, your work never leaves your browser.
• With an account, your work is stored so that you can reach it from your other devices. It is not used for anything else.
• There is no advertising and no tracking, and nothing is sold or shared for marketing.
• You can delete your saved work, or your whole account, at any time.
• Payments are taken by Stripe. Slide Rule never sees or stores your card details.

If you do not sign in

Everything you enter (calculations, worksheets, graphs, settings) is kept in your browser's own storage on your device. It is not sent to us. Clearing your browser's site data removes it.

If you sign in

Signing in is done with your Google account. Google tells us your name, your email address, the address of your profile picture, and an identifier for your Google account. We never see your Google password, and we do not ask Google for anything else.

Once you are signed in, the following is saved to your account so that it follows you between devices: your worksheets; stored values and functions; the calculator and matrix history; formulas you have added; what is on the Graph, Statistics and differential-equation tabs; and your settings.

We use this only to provide the service to you: to show you your own work when you sign in. We do not read it for any other purpose, and we do not use it for advertising or sell it.

Who else handles it

Slide Rule relies on a small number of service providers, who process information on our behalf:

• Supabase provides the sign-in service and the database where accounts and saved work are kept.
• Cloudflare delivers the website to your browser and, on networks that cannot reach the database directly, passes your requests on to it.
• Google provides sign-in, and the fonts the site uses.
• Stripe takes payments for paid plans. See Payments, below.
• Resend delivers the verification code if you verify as a student. It is given the address the code is sent to, and nothing else.

As with any website, these providers see technical details such as your IP address and browser type when your device connects to them. Their servers may be outside Australia.

Storage in your browser

Slide Rule uses your browser's local storage to keep your work, your settings and, if you sign in, the record that you are signed in. It does not use advertising or tracking cookies.

Keeping and deleting

Saved work is kept until you delete it. Under Settings ▸ Account you can delete your saved work, or delete your account together with everything saved in it. Deletion is permanent. Signing out clears your work from the browser you are using; it remains in your account.

Two things remain after an account is deleted. The first is a one-way fingerprint of the account's email address, kept so that the free trial is given once to each person; the address cannot be worked back from it, and it is not used for anything else. The second is the record of any payments, which Stripe keeps as the law requires of it.

Security

Connections to Slide Rule are encrypted. Saved work is stored so that each account can only reach its own. No system is perfectly secure, so please do not store anything in Slide Rule that would cause you harm if it were disclosed.

Children

To sign in you need a Google account, and must meet Google's age requirements for having one.

Payments

If you subscribe to a paid plan, you pay on a page run by Stripe. Your card details go to Stripe and are never seen or stored by Slide Rule. Stripe receives your email address from us so that it can send receipts and recognise you if you subscribe again, and it uses what it collects to take the payment and to prevent fraud, under its own privacy policy.

We keep, with your account: which plan you are on, when it renews or ends, whether it has been cancelled, when your free trial ends, and Stripe's reference numbers for you and your subscription. We do not keep your card number, billing address or payment history; those are with Stripe, and you can see and change them under Settings ▸ Account ▸ Manage subscription.

Student verification

To get the student price you give the email address of your university, college or school, and a code is sent to it to show the address is yours. We keep, with your account, that address and the date your verification runs out. The address is used to stop one student address verifying more than one account, and to contact you about your student status; it is not used for marketing. A code is kept only as a fingerprint, for at most a few minutes.

Changes

If this policy changes, the date at the top will change, and significant changes will be announced in the app.

Contact

Questions about your privacy, or requests about your information: Email support@sliderule.com.au.