All in One Calculator guide
How to Choose a Maths Calculator App
Look for an app that shows its working rather than just the answer, runs offline, and does not interrupt you with ads. Check whether the useful features are behind a subscription before you install, and check your exam board rules if you plan to use it in a test.
A note before the advice
This site is run by the developer of the calculators it describes, so treat any recommendation here with the scepticism that deserves.
What follows is the checklist we would give a friend, written to be useful even if you end up installing something else entirely. Every calculator on this site is free to use on the web with no account, so you can test the maths before deciding whether any app is worth your money.
Does it show the working?
This is the one that matters most, and it is the one most often missing.
An app that gives you 5 and −3 has saved you two minutes. An app that shows you the discriminant, both branches of the formula and the substitution has taught you something you can use in the exam, where the app will not be.
Be careful here: several of the best-known apps show the answer free and put the steps behind a subscription. That is a legitimate business model, but it means the free version is doing the opposite of what a student needs.
Does it work offline?
A calculator that needs a connection is a calculator that fails on a train, in a basement classroom, or anywhere the school Wi-Fi is having a day.
Anything doing the arithmetic on your device will work offline. Anything sending your problem to a server for an AI to interpret will not.
It is worth knowing which kind you have installed before you are relying on it.
Ads, subscriptions and what you actually get
Free calculator apps are usually paid for in one of three ways: advertising, a subscription, or a one-off purchase.
Ads are the worst option for a calculator specifically. A full-screen advert between entering your numbers and reading the answer is disruptive in a way it would not be in a game.
Subscriptions are worth checking carefully. Ask what is actually free, and what needs paying for. Steps behind a paywall is common.
One-off purchases cost more up front and nothing afterwards.
To be explicit about our own: the six single-purpose apps are free downloads, with AI explanations and dark mode available through an optional PRO subscription. All in One is a paid app — a single purchase, no ads, no subscription — and it contains all six calculators.
Check the exam rules before you rely on it
No phone app is permitted in a formal exam. Not one, regardless of what it does.
That is worth planning around rather than discovering on the day. If you have done all your practice on a phone, you will be slower with the handheld calculator you are actually allowed.
The sensible use of a calculator app is checking work at home, not replacing the device you will sit the exam with. Practise on the calculator you will be examined with, and use the app to verify your answers afterwards.
The checklist
- Does it show the steps, and are they free?
- Does it work with no internet connection?
- Are there ads, and do they interrupt the calculation?
- If there is a subscription, what exactly is behind it?
- Does it cover the topics you actually study?
- Can you try it before paying?
