Terms of use

Last updated 7 October 2026. By using Slide Rule you agree to these terms. Slide Rule is run by Jesse Delahunty Dunning (ABN 76 715 112 597), in Australia.

The service

Slide Rule is a set of tools for calculation, reference and study. You can use it without an account; signing in adds saving your work to an account. Features may be added, changed or removed over time.

Check your results

Slide Rule is a study and working aid. Every effort is made to keep its calculations and reference data correct, but errors are possible, both in the software and in what is typed into it. You are responsible for checking results before relying on them. Do not rely on Slide Rule alone for any decision where a mistake could cause injury, damage or significant loss, including engineering design, medical or safety-critical work.

Your account

You sign in with a Google account and are responsible for keeping it secure. Tell us if you believe someone else has used your account. You may delete your account at any time under Settings ▸ Account.

Your work

What you create in Slide Rule is yours. By saving it to your account you allow us to store it and send it to your devices, which is the whole of what we do with it. See the Privacy policy for details.

Acceptable use

Please do not misuse the service: do not try to reach other people's accounts or data, interfere with the service or overload it, or use it to break the law. Your place of study may have its own rules about which tools may be used in assessments and examinations; following them is up to you.

Plans and payment

Slide Rule has a free plan and a paid plan, Pro. The free plan includes every tool. Pro adds what is listed under Help ▸ Plans and payment: worksheets without limits, exporting, saving graphs as images, bringing tables in from a spreadsheet, and colour palettes.

Free trial. A new account has Pro free for 14 days. No payment details are asked for. When the trial ends the account moves to the free plan by itself and nothing is charged. There is one trial for each person.

Prices. Pro is $24.99 a month or $199.99 a year. For students whose status has been verified it is $9.99 a month or $79.99 a year. Prices are in Australian dollars. The price you will pay is shown on the payment page before you pay.

Paying and renewing. A plan is paid for in advance, for a month or a year. It renews by itself at the end of each period, and the payment method you gave is charged again, until you cancel. Payments are taken by Stripe; we never see or hold your card details. If a payment fails it is tried again over the following days, and if it still fails the account moves to the free plan.

Cancelling. You can cancel at any time under Settings ▸ Account ▸ Manage subscription. Pro then stays until the end of the period already paid for, and is not charged again. After that the account is on the free plan. Nothing you have made is deleted: the free plan limits what can be added, not what is kept.

Refunds. A payment for a yearly plan is refunded in full if you ask within 14 days of that payment, and Pro ends when it is refunded. Monthly payments are not refunded for a part of a month; cancelling stops the next one. To ask for a refund, email support@sliderule.com.au from the address of your account. This is in addition to, and does not limit, your rights under the Australian Consumer Law.

Student prices. The student price is for people enrolled at a school, college or university, and needs your student status to be verified, with an email address from your place of study. One address verifies one account. Verification lasts a year, and you will be reminded by email before it runs out. If it runs out while you are on a student plan, the plan is set not to renew: you keep Pro to the end of the period you have paid for, and the account then moves to the free plan. Nothing more is charged. If you verify again before the plan ends, it carries on at the student price.

Changes to prices. If the price of your plan is going to change, you will be told by email at least 30 days before the first renewal at the new price, so that you can cancel first if you wish.

Deleting your account ends a subscription straight away. The time left on it is not refunded, except as set out under Refunds.

Availability

We aim to keep Slide Rule available, but it may be interrupted or unavailable from time to time, and it may be changed or withdrawn. Keep your own copy of anything important: a worksheet can be exported as a PDF.

Liability

Slide Rule is provided as it is. To the extent the law allows, we are not liable for loss or damage arising from the use of, or inability to use, the service, including from errors in results or the loss of saved work. Nothing in these terms excludes or limits any guarantee, right or remedy that cannot be excluded or limited by law, including under the Australian Consumer Law.

Ending use

You can stop using Slide Rule at any time. We may suspend or close an account that is used in breach of these terms.

Changes and law

These terms may be updated; the date at the top shows the latest version, and continuing to use Slide Rule after a change means you accept it. These terms are governed by the law in force in Australia.

Contact

Email support@sliderule.com.au.