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Every September, students arrive in Year 12 with the calculator they used at GCSE. Most of them find out within a fortnight that it will not do what the course asks of it, and a few do not find out until the statistics unit, by which point they have spent months doing things the slow way.
This guide covers what you actually need, what we would buy, and the one question worth asking before you spend anything.
In this guide
Before you buy anything, ask your school
This matters more than anything else in this article, so it goes first.
Most schools and colleges recommend a specific calculator, and there is a good reason for it. Teaching a class is far more effective when everybody is holding the same model. The teacher can put the exact key sequence on the board, students can help each other, and nobody spends half a lesson hunting for a menu that sits somewhere else on their machine.
The reverse is also true. If you turn up with a model nobody in the department uses, and you cannot find a function or something goes wrong, you are on your own. That is extra work you have chosen to take on, and at A Level you have better things to spend your time on.
Ask first. Email your maths department, or ask in your first lesson, whether they recommend a particular calculator. If they do, follow that over anything below. The rest of this guide is for students whose school leaves the choice to them.
What the exam boards actually require
Edexcel, AQA and OCR all set the same practical minimum for A Level Maths. Your calculator has to be able to:
- Handle an iterative procedure, so you can repeat a calculation using the previous answer.
- Compute summary statistics from a data set, such as the mean and standard deviation.
- Give you probabilities from the binomial and normal distributions, including the cumulative versions.
There is a limit at the top end too. Calculators that perform symbolic algebra or symbolic calculus, usually called CAS models, are not allowed in any A Level Maths exam. If it shows you the algebraic steps of a solution, it is out. Graphical calculators without that feature are permitted in every A Level Maths and Further Maths paper.
Why a GCSE calculator runs out long before the statistics
It is tempting to read the list above, notice the word statistics, and conclude that your old calculator will be fine until next summer. It will not.
The GCSE workhorses, the Casio fx-83 and fx-85 families, are built for a different course. They will handle arithmetic, trigonometry, powers and the standard deviation of a list of numbers perfectly well. What they cannot do is most of what makes A Level quicker:
- Solve an equation. No quadratic or cubic solver, so every time you want to check the roots of a quadratic you are doing it by hand while the rest of the class presses one button. This starts in the first few weeks of Year 12.
- Solve simultaneous equations, which turn up everywhere from coordinate geometry to mechanics.
- Evaluate a definite integral or a gradient numerically, which is the fastest check there is that your calculus is right.
- Give you the binomial and normal distributions, the requirement above, which is the point at which the calculator stops being merely slow and starts being unusable.
- Handle matrices, vectors and complex numbers, if you are taking Further Maths.
None of that is a criticism of those calculators. They do the job they were designed for. The point is simply that A Level asks for more, and it asks early, so the upgrade is not something to put off until the statistics unit arrives.
In short: your GCSE calculator is not enough, and the most powerful calculators on the market are not allowed. The right choice sits between the two, and there are only two decisions to make: graphical or scientific, and which model.
Our pick: the Casio fx-CG100
If you can afford it, and you are willing to learn how to use it, the Casio fx-CG100 is the calculator we would point most A Level students towards. It is the current top of the range Casio graphical calculator for UK schools, it is approved for every UK exam including A Level, Further Maths and the IB, and it replaces the model that dominated sixth forms for years.
That model was the fx-CG50, and it has now been discontinued. Casio stopped manufacturing it and expected the last stock to clear during autumn 2025, with the classroom emulator retiring during the 2026 to 2027 academic year. Existing CG50s are still perfectly legal in exams and still excellent, but a new one is buying into a model on the way out.
Casio fx-CG100
Does everything the CG50 did, with a friendlier interface and a screen that is genuinely easy to read. The one to buy if you will put the hours in.
- Menu driven, with far fewer cryptic abbreviations to decode
- High resolution colour backlit screen
- One press FORMAT key for exact and decimal answers
- Inequality solver, improved Graph and Table, Python built in
- Approved for GCSE, A Level, Further Maths, Highers and IB
The obvious drawback is the price. Graphical calculators sit at around a hundred pounds, which is a lot next to a scientific calculator at under thirty. It is worth being honest with yourself about whether you will get that back.
Is a graphical calculator worth it for you?
Here is the part most buying guides skip.
A graphical calculator is only worth buying if you are willing to learn how to use it.
Sitting an exam with a hundred pound calculator you can only use as a very expensive scientific calculator is a waste of money, and worse, it costs you time while you hunt through menus under pressure. If you are not going to put the hours in during Year 12, buy a good scientific calculator and spend the difference on something useful.
For most of the course, the calculator you own makes very little difference. Differentiation, integration by parts, trigonometric identities, proof, vectors, most of mechanics: none of it cares what is in your hand.
Where a graphical calculator genuinely pulls ahead:
- Critical regions in hypothesis testing. A graphical calculator has an inverse binomial function, so you go straight from a probability to the boundary value. A scientific calculator gives you cumulative probabilities only, so you test values one at a time until you find the boundary. This is the clearest case where the better calculator saves real time in an exam.
- Seeing the graph. Roots, intersections, turning points, asymptotes and transformations are all easier to reason about when you can look at the curve. It is also a fast sanity check: if your algebra gives three roots and the screen shows one, you know to go back.
- Equation solving. Polynomials, simultaneous equations and numerical solutions, quicker and over more cases.
- Iteration and numerical methods. Watching a staircase or cobweb diagram converge makes the topic far less abstract.
- Tables of values for sketching, checking a change of sign, or spotting behaviour you have missed.
The honest test: will you spend an hour or two, several times over the year, learning what your calculator can do and practising until it is automatic? If yes, it is a good investment. If not, there is no shame in a scientific one, and you will not be at any real disadvantage across the vast majority of the course.
The other graphical options
Casio fx-CG50
The model most UK teaching resources and tutorial videos were written for. Discontinued, but exam approved and still excellent, so a hand me down or a sensibly priced new one is a good buy.
- Everything you need for A Level and Further Maths
- The largest library of UK classroom material of any graphical calculator
- Stock is drying up and the emulator is being retired
Casio fx-9750GIII
The budget way into graphical. The core A Level functionality including the distributions, on a monochrome screen and with a more basic feel.
- Cheapest sensible route to inverse binomial and graphing
- Same broad menu logic as the colour Casio models
- No colour, no backlight
Texas Instruments TI-84 Plus CE
Capable, well built and permitted in UK exams. The catch here is support: the key sequences differ from Casio, and most UK classroom material assumes a Casio.
- Strong choice if your school teaches with Texas Instruments
- Large international community and resource base
- Fewer UK specific tutorials for A Level topics
There is also NumWorks, a modern and well designed calculator with a clean interface and Python built in. Check its exam status carefully, and check whether anyone around you knows it, because UK teaching support for it is thin compared with Casio.
If you are going scientific: the fx-991CW+
If you have decided against a graphical calculator, you still need one that clears the bar in section two. The default choice for A Level Maths is the Casio fx-991CW, and there is now a revised version, the fx-991CW+, which is the one to look for.
The original CW arrived with a redesigned menu system that divided opinion. The most common complaint was that switching between fractions and decimals, something you do constantly, took more presses than it used to. The CW+ addresses several of those points.
Casio fx-991CW+
Everything A Level asks of a scientific calculator, and it fixes the things people disliked about the original CW. For most students this is the sensible buy.
- One press FORMAT toggle between exact and decimal answers
- Binomial and normal distributions, equation solving, integration and differentiation
- Adds highest common factor, lowest common multiple and recurring decimals
- Catalog and number key shortcuts, so less scrolling
Either version will do the job and both are approved for GCSE and A Level. If the CW+ is on the shelf where you are shopping, take it.
What about the fx-991EX?
For years the fx-991EX was the scientific calculator everybody had, and plenty of teachers and students still consider it the better machine. If you have one, whether it is yours from GCSE or a hand me down from an older sibling, keep using it. It is sturdy, fast, well laid out, and it does everything A Level Maths requires.
Buying one now is a different matter. It has been superseded, so genuine new stock is hard to find, and a large proportion of what is offered cheaply through online marketplaces is counterfeit. This is not a cosmetic problem. Counterfeit units have been reported to return incorrect results on calculations, which is close to the worst possible failure in something you are trusting in an exam.
Check a suspect unit. Casio publishes an authenticity check: on a genuine ClassWiz you can bring up a QR code from the settings menu and scan it with a phone, and it should take you to Casio's own site. A unit that produces no QR code, or one that will not scan, should be treated as suspect.
You will notice there is no buy link in this section. We are not going to send you to a marketplace listing for a discontinued model where the counterfeit rate is this high, affiliate commission or not. A new fx-991CW+ costs about the same and is certainly genuine.
The rules on exam day
Whatever you buy, the regulations put the responsibility on you rather than on the school. Before every paper you are expected to:
- Make sure the calculator works and the batteries are good. Change them before the exam season starts, not on the morning.
- Clear the memory, including anything stored in variables or programs.
- Remove any case, lid or cover with printed instructions or formulae on it. Plenty of calculators have exactly that on the back of the lid.
Calculators must also be quiet, hand held and self powered, and must not hold retrievable information such as databanks or notes. Scientific constants are fine.
The short answer
| Calculator | Who it suits | Rough cost |
|---|---|---|
| Casio fx-CG100 | Our pick, if you will learn to use it properly | Around £100 |
| Casio fx-CG50 | Excellent if handed down or found new, but discontinued | Around £100 |
| Casio fx-9750GIII | Graphical features on a tighter budget | Around £60 |
| Casio fx-991CW+ | The scientific default, and the right call for many students | £25 to £30 |
| Casio fx-991EX | Great if you already have one, risky to buy secondhand | Varies |
Check with your school first. If the choice is yours and the budget allows, buy the fx-CG100 and commit to learning it. If it does not, or you know you will not put the time in, buy the fx-991CW+ and get very good at it. A student who knows their scientific calculator inside out will usually do better than a student who owns a graphical calculator and has never opened the manual.
Whichever you choose, learn it in Year 12, not the week before your first paper. The calculator is a tool, and like every other tool at A Level, the value is in the practice.
Prices are a guide only and move around. Before you order, it is worth comparing your school's supplier, Casio's own store and the usual stationers as well as Amazon: the cheapest place changes through the year, and back to school season is rarely the low point.