Best A-Level Maths Calculator: AQA, Edexcel and OCR Rules

For A-Level Maths, the safest pick is a Casio scientific or graphical model that Casio lists as permitted in all UK examinations: the fx-991CW or the graphical fx-CG50 (Casio's 2025 “Calculators in examinations” leaflet; eligibility can change, so check your centre's current list). Whichever model you buy needs the features your exam board's specification names. This guide takes those from the specifications themselves and shows the skills they ask for with worked numbers you can check.

What the exam boards require

The A-Level Maths specifications from AQA, Edexcel and OCR each name the functions a calculator needs. The table gives their wording.

AQA's minimum also lists an inverse normal function. Read the current specification for your own course, because boards update them.

What is allowed in the exam room

Edexcel's specification lists what a calculator must not offer: language translators, symbolic algebra manipulation, symbolic differentiation or integration, and communication with other machines or the internet. It must not have retrievable information stored, such as databanks, dictionaries, mathematical formulas or text. These match the JCQ rules for exams, which the AQA and OCR specifications also point to.

A calculator with a computer algebra system offers symbolic algebra, so it is not allowed as it stands. The JCQ rules add that some calculators have an “exam mode”, which is acceptable where the mode is activated and makes the calculator meet the rules.

OCR's specification permits “a scientific or graphical calculator” for all papers. AQA's specification points to the JCQ rules and Edexcel sets out its own list, so check the current rules before an exam.

Models Casio lists as permitted

Casio's 2025 “Calculators in examinations” leaflet gives the exam eligibility of its own models:

• fx-991CW and fx-991EX: “permitted in all UK examinations”. The leaflet notes that the fx-991EX has been discontinued.
• fx-CG50 (graphical): “permitted in all UK examinations”.

The fx-991EX user's guide shows what such a model offers against the boards' lists. Its Distribution mode has Normal PD, Normal CD, Inverse Normal, Binomial PD, Binomial CD, Poisson PD and Poisson CD. It stores the last result in Ans, the kind of key OCR's wording describes for iteration, and it has Matrix, Vector, Complex, Spreadsheet and Equation modes. Models differ, so look for the same items on any calculator you consider.

Skills the specifications ask for

Iteration with the Ans key

To find the root of $x^3 - 5x + 1 = 0$ near $x = 2$, rearrange to $x = \sqrt[3]{5x - 1}$ and iterate:

1. Type 2 and press equals, so that Ans holds 2.
2. Type $(5 \times \text{Ans} - 1)^{1/3}$ and press equals again and again.
3. The values run 2, 2.0801, 2.1105, 2.1218 and on to 2.1284.

That is the first step of the iteration $x_{n+1} = \sqrt[3]{5x_n - 1}$ starting at $x_0 = 2$. This calculator has no Ans key, so for the next step type the answer in place of 2 and press equals. On an exam calculator, press Ans and equals to repeat it.

Binomial probabilities

Suppose $X \sim B(20, 0.3)$ and you need $P(X \leq 5)$. In the calculator's binomial cumulative mode, enter x = 5, N = 20 and p = 0.3. The answer is 0.4164.

Normal probabilities

Suppose $X \sim N(50, 16)$. The second number is the variance, so the standard deviation to enter is $\sigma = 4$. For $P(X \leq 55)$, use normal cumulative mode with a lower bound far below the mean, such as 30 (5 standard deviations under it), upper bound 55, $\sigma = 4$ and $\mu = 50$. The answer is 0.8944.

To go the other way, the inverse normal function takes an area to its left, with the standard deviation and mean, and returns the value. The fx-991EX guide says its inverse normal tail setting is always left.

Checking a definite integral

Take $\int_{1}^{3} (3x^2 - 2x + 1)\,dx$. An antiderivative is $x^3 - x^2 + x$, so the value is $21 - 1 = 20$. A calculator's integral function can confirm 20.

Use it to check, not to replace the method. OCR's specification says that on “show detailed reasoning” questions, just writing down the answer from the definite integral function would not be awarded any marks, and advises candidates to write down explicitly any expressions, including integrals, that they use the calculator to evaluate. It also says correct mathematical notation, not “calculator notation”, should be used.

Choosing one

• Check the model is on your exam centre's permitted list for the current year.
• Find the features in your board's table above on the model: an iterative function, summary statistics, distribution probabilities and, for AQA, an inverse normal.
• Clear anything stored that the rules forbid, such as formulas or text.
• Practise the skills above until the keys are familiar.

Frequently asked questions

Can I use a calculator in every A-Level Maths paper?

The AQA, Edexcel and OCR specifications each allow a calculator in all of their A-Level Maths papers. AQA says one is required for all assessments. Check the specification for the course you are taking.

Do I need a graphical calculator?

The specifications ask for features, not a screen type. OCR says a scientific or graphical calculator is permitted, so either can meet them.

Is the Casio fx-991EX allowed?

Casio's 2025 leaflet lists the fx-991CW and fx-991EX as permitted in all UK examinations, and says the fx-991EX has been discontinued.

Does the variance or the standard deviation go into the calculator?

The standard deviation. For $N(50, 16)$ the second number is the variance, so enter $\sigma = 4$.