Click an empty cell to add a card, and drag a card by its dots to move it. Enter starts a card below. On an empty card, # makes a title and " a note. Type _ for a subscript, as in FN. A graph card can plot functions, a 3D surface or a table of data, work out a probability or a hypothesis test, or solve a differential equation, and can use any value on the sheet by name (a value with a unit counts as the number shown on its card). A number followed by a unit is always the unit, so 2 m is two metres even when the sheet has a value called m; write 2×m to multiply. Each sheet keeps its own values, separate from the calculator.
Calculator
Type or use the keys, and it's laid out as you'd write it. Click any part of the expression to edit it. Press Enter to evaluate.
Variables
Quick reference
- /
- Makes a fraction from what you just typed
- ^
- Starts an exponent. Press → or ▶ to leave it
- ( )
- Open and close brackets separately, so you can wrap something already typed. A bracket left open is closed at the end
- d/dx ∂/∂x ∫ ∫ₐᵇ
- Derivative, partial derivative, antiderivative and definite integral. On its own, each gives the formula. Click the x in dx to change the variable
- simplify expand
- Collect like terms and cancel factors, or multiply the brackets out
- 2x + 3 = 11
- Type an equation and press = to solve it. solve does the same and lets you choose the letter to solve for
- factor lim series
- Factorise a polynomial, find a limit (type inf for ∞), or build a Taylor series
- matrices
- Matrices, vectors and simultaneous equations are in Solvers. A matrix stored there under a letter, or pasted here, still works in a calculation
- 5∠30
- A phasor: size and angle. Complex answers also show their polar form
- wrap
- Type the expression first, then press d/dx, ∫, simplify or expand: it goes inside. With part selected, any function key wraps just that part
- select
- Drag across part of the entry, or hold Shift with ← →. Double-click selects what is under the pointer, and each further click takes in the next level out: a number, then its fraction, then the matrix entry, then the matrix. Ctrl+A selects everything. Copy, cut, paste and typing then act on the selection
- |ₓ₌ₐ
- Evaluate what you have typed at a value, such as x = 2
- 2x + 3x
- Letters with no stored value stay as letters, and the expression is simplified
- click any part
- Put the cursor there to change or delete it, including an exponent or a root's index
- sqrt( cbrt( root(
- Type a root, or use √ and ʸ√x
- log( ln( |
- log is base 10 (click the 10 to change the base), ln is natural, | is absolute value
- x = 4.2
- Store a variable, then use it anywhere
- 2.31 ± 0.02
- A measurement with uncertainty. Results carry the propagated ± through every step
- f(x) = x^2 + 1
- Define your own function
- 60 mph to m/s
- Unit conversion inline
- Show working
- Opens the steps for a calculation, naming the rule used at each one: derivatives, integrals, algebra, solving equations, limits, matrices and complex numbers. Steps on a history line shows that line's working
- history
- Click a calculation to bring it back for editing, or its answer to use the result
- Copy Paste
- Copy the whole entry or paste text into it. Ctrl+C, Ctrl+X and Ctrl+V work too
- ↑ ↓
- Recall earlier calculations
- Esc
- Clear the entry
Unit converter
Pick a quantity, enter a value, and every unit in that family updates at once.
Convert any expression
Write a quantity, then to and the unit you want. Compound units are fine.
Reference data
Physical constants, the periodic table, material data, steam and property tables, and section properties. Click a value to copy it or send it to the calculator with its units.
Inserts
Material values are typical figures from standard references (CRC Handbook, NIST, Çengel & Ghajar, ASM/MatWeb). Real values vary with grade, temper, purity and temperature, so check a datasheet for design work.
Formula solver
Choose the quantity to solve for, fill in the rest, and the answer updates as you type. Every formula uses SI units.
Graph
Plot functions, equations, inequalities, parametric and polar curves, with sliders. Drag to pan, scroll or pinch to zoom, hover to read values.
Expressions
Try
Spare letters such as a become sliders. Angles are in radians.
Analyze
Derivative
f′() =
Indefinite integral
Definite integral
∫
f(x) dx =
Roots in view
Min / max in view
Intersections in view
Surfaces z = f(x, y)
x from to
y from to
Analyze
Partial derivatives
At a point(, )
Critical points in the domain
Volume under the surface
Min / max on the domain
Drag to rotate · scroll or pinch to zoom
Data
Curve fit
y =
Type any function of x. Every other letter becomes a parameter to fit. A function with no parameters is simply plotted against the data.
Model at x =→ y =
Statistics
Statistics
Probabilities from common distributions, and hypothesis tests with confidence intervals.
Alternative H₁
Result
Solvers
Matrices, vectors and simultaneous equations with step-by-step working, and differential equations.
Try one
Variables
Quick reference
- matrix
- Fill in the grid. , moves to the next cell and ; starts a new row, adding one when needed. Backspace in an empty row or column removes it
- [1, 2; 3, 4]
- Typing square brackets builds the same grid from the keyboard
- A = …
- Store a matrix under a letter, then use it: A*B, A^-1, det(A). Stored values are shared with the calculator
- + − × ^
- Matrices add, subtract and multiply as written. ^-1 is the inverse and ^2 multiplies the matrix by itself
- det rref eig
- Type the matrix first, then press the key: it goes inside. Also rank, trace and transpose
- vector
- One row of numbers. dot, cross and angle take two vectors separated by a comma
- system
- Simultaneous equations, one per line. ; or +eqn adds a line. Typing x + y = 3; x − y = 1 does the same
- paste
- Rows copied from a spreadsheet paste in as a matrix
- Show working
- Row operations, cofactor expansions and each entry of a product, step by step. Steps on a history line shows that line's working
- history
- Click a calculation to bring it back for editing, or its answer to use the result
Initial conditions
t from to
Values at t =
Settings
Your account, how Slide Rule looks, help, and the small print.
Account
No account here
Accounts are part of the Slide Rule website. In this preview your work is kept in this browser only.
Account
Sign in to save your work
Your worksheets, stored values, calculator history, graphs and your own formulas are saved to your account, and are there on any device you sign in on. What is already in this browser is added when you sign in.
New accounts get Pro free for 14 days. No card is needed, and nothing is charged when the trial ends.
Trouble signing in? Sign in another way.
By signing in you agree to the Terms of use and Privacy policy.
Signed in as
Signing out clears your work from this browser. It stays in your account, ready for the next time you sign in.
Plan
Prices are in Australian dollars. Payment is taken by Stripe: Slide Rule never sees your card. A plan renews until you cancel it. A yearly plan is refunded in full within 14 days of paying; see the Terms.
A 6-digit code is emailed to it, to show the address is yours. It is used for nothing else.
Your data
Delete what is saved
Delete saved work removes every worksheet, stored value, history, graph and formula saved in your account, here and on your other devices, and keeps the account. Delete account removes the account as well. Neither can be undone.
Theme
Light or dark
Auto follows your device.
Colour
Colour palette
Help
Short answers to the questions that come up most. Each tool also has a Quick reference beside it.
Getting started
What is Slide Rule?
A toolkit for engineering and science work: a calculator that shows its working, a unit converter, reference data, a formula solver, graphing, solvers for matrices and differential equations, statistics, and a worksheet for laying out a whole problem.
Do I need an account?
No. Without one, everything you do is kept in this browser. Signing in saves your work to your account, so it is there on any device you sign in on.
Can I use it offline?
Yes. Open the site once while online and it keeps working without a connection. On a phone or computer you can also install it from the browser menu ("Install" or "Add to Home Screen"). Work done offline is sent to your account when you are back online.
Your account and saved work
What is saved to my account?
Worksheets, stored values, the calculator and matrix history, your own formulas, what is on the Graph, Statistics and differential-equation tabs, and your settings.
Why did the page reload on its own?
Newer work was found in your account, from another device. The page loads again so that every tool shows it. This only happens when you open the app, come back to its tab, or press Sync now, never while you are typing.
Why do I have a worksheet called "… (this device)"?
The same worksheet was changed on two devices before they could sync. Rather than choose one and lose the other, both are kept: the copy marked "(this device)" is the one from the device you are on. Keep whichever you want and delete the other.
What happens when I sign out?
Your work is cleared from this browser, so the next person at a shared computer does not find it. It stays in your account and comes back when you sign in.
How do I delete my work or my account?
Under Settings ▸ Account. "Delete saved work" removes everything saved in your account and keeps the account. "Delete account" removes the account as well. Neither can be undone.
Plans and payment
What is the difference between Free and Pro?
The free plan has every tool: the calculator and its working, units, reference, formulas, graphing, the solvers, statistics and the worksheet. Pro adds what leaves the app or goes beyond one sheet: as many worksheets as you like, with no limit on cards or graphs; exporting a worksheet as a PDF, a printout or LaTeX; saving any graph as an image; pasting tables in from Excel or Sheets and saving data and results as CSV; and the colour palettes.
How does the free trial work?
A new account has Pro for 14 days. No card is asked for. When the trial ends, the account moves to the free plan by itself: nothing is charged, and nothing you made is deleted. Settings ▸ Account shows how many days are left.
How much is Pro?
$24.99 a month, or $199.99 a year. For verified students it is $9.99 a month or $79.99 a year. Prices are in Australian dollars. You subscribe under Settings ▸ Account, and pay on a page run by Stripe.
How do I get the student price?
Sign in, then under Settings ▸ Account press Verify student status and type the email address your university, college or school gave you. A 6-digit code is emailed to it; type the code back and you are verified for a year. If you signed in to Slide Rule with that address, no code is needed. Verify before subscribing, so that the student price is the one you are charged. If you already pay the standard price, email support@sliderule.com.au after verifying and your plan will be moved.
What happens when my student verification runs out?
Verification lasts a year. You are emailed a month before it runs out and again a week before, and can verify again at any time under Settings ▸ Account. If it does run out while you are on a student plan, the plan is set not to renew: you keep Pro to the end of what you have paid for, then the account moves to the free plan. You are not charged the standard price, and nothing you made is deleted. Verify again before the plan ends and it carries on as before.
My student address is not accepted, or the code has not come
Codes can take a minute and sometimes land in junk mail; a new one can be asked for after half a minute. The address has to be the one from your place of study, not a personal one. If it is and Slide Rule still does not recognise it, email support@sliderule.com.au from that address and it will be checked by hand.
How do I cancel, or change my card?
Under Settings ▸ Account, press Manage subscription. From there you can cancel, change the card, move between monthly and yearly, and see your invoices. After cancelling you keep Pro to the end of the period you have paid for, and are not charged again.
Can I have a refund?
A yearly payment is refunded in full if you ask within 14 days of it. Monthly payments are not refunded for part of a month; cancelling stops the next one. To ask, email support@sliderule.com.au from the address of your account. Your rights under consumer law are not affected.
What happens to my work if I go back to Free?
It all stays. Every worksheet can still be opened and edited. The free plan limits what can be added: new worksheets beyond the first, and cards or graphs beyond the free allowance on a sheet.
I paid, but the app still says Free
It can take a minute for a payment to reach your account. Under Settings ▸ Account press Sync now, or reload the page. If it has not changed after a few minutes, email support@sliderule.com.au and it will be put right.
Using the tools
How do I see the steps of a calculation?
Press Show working in the Calculator or the matrix solver, or the working button on a worksheet card. Each step names the rule it used.
Why is my answer a fraction (or a decimal)?
A calculation typed without decimals has an exact answer, shown as a fraction. The Fractions control (Auto, Always, Never) beside the calculator changes this. Values with units are always decimals.
How do I use a value from Reference or Formulas?
Click the value, then "Use in calculator" or "Add to worksheet".
How do I save a worksheet as a PDF?
On the Worksheet tab press Export, choose the layout, then Save PDF. Nothing is cut across a page: a card that would not fit moves to the next one.
Are there keyboard shortcuts?
Press / to search everything, and Alt with 1 to 8 to switch tools. In an entry, / makes a fraction, ^ a power and _ a subscript.
Something is wrong
Signing in does not work
Pressing Continue with Google opens Google's sign-in in a small window: if nothing appears, allow pop-ups for this site and try again. If it still fails, use "Sign in another way" under the button. If that shows "This site can't be reached", your network is blocking the sign-in service: try another network, such as mobile data.
My work is not appearing on my other device
Check that both devices are signed in to the same Google account. On the device with the work, open Settings ▸ Account and wait for "All work saved to your account"; on the other, press Sync now.
An answer looks wrong
Check the angle setting (DEG or RAD) and the units first, then press Show working to see where it departs from what you expected. If you think Slide Rule itself is wrong, please tell us, with the calculation you typed.
Contact
Email support@sliderule.com.au.
Privacy policy
Last updated 6 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.
Terms of use
Last updated 6 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. While Slide Rule is in preview, everything is open to everyone and nothing is charged. You will be told in the app before paid plans start.
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.
Worksheet
Lay a problem out as cards on a grid. A card can use a value from any other card, so you can drag them around freely. Save the finished sheet as a PDF or as LaTeX.
Printing is blocked in this view, so the sheet was saved as a web page instead. Open that file and choose Print, or use Save PDF on the export screen, which makes the file directly.