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IB Mathematics

Which Graphing Calculator to Buy for IB Maths

On the IB, the graphing calculator is not an extra: entire papers are designed around it. Which model I recommend, what is banned, and four things it solves in seconds.

By Álvaro López · 17 October 2026 · 8 min read

Students who arrive at the IB from Spanish secondary school (ESO) often think a graphing calculator is just for "drawing pictures". Far from it: the calculator papers include questions that are either solved on the screen or not solved at all, such as an intersection between an exponential and a parabola. Knowing how to use it well earns marks.

My recommendation: the Casio fx-CG50. It is approved for the IB, the colour screen is very easy to read, and it has everything AA and AI require without making life complicated.
Casio fx-CG50 graphing calculator showing a 3D graph on screen
Casio fx-CG50. Image: Casio.

Casio fx-CG50

  • High-resolution colour screen
  • 2D, conic and 3D graphs
  • G-Solv: roots, maxima, minima, intersections
  • Statistics, regressions and distributions
  • Equation solving and matrices
  • No CAS: allowed in IB exams

Which papers use it

SubjectCalculator papers
Math AA SLPaper 2
Math AA HLPapers 2 and 3
Math AI SLPapers 1 and 2
Math AI HLPapers 1, 2 and 3

In AI the calculator is used in every paper, and much of the course (statistics, models, regressions) revolves around it. In AA, Paper 1 is calculator-free, but Paper 2 includes questions designed to be solved graphically. If you are deciding between the two, I explain it in IB Math AA vs AI: which to choose.

The CAS trap

IB exams only allow graphing calculators without computer algebra (CAS). Some models from other brands are sold in a normal version and a CAS version that look almost identical. With the fx-CG50 there is no doubt: it has no CAS.

Four things it solves in the exam

These are the situations that come up most often in the calculator papers. The animations show what you would see on screen; under each one is the menu you use.

1. Maxima and minima of a function

Y1 = X³ − 3X MAX (−1, 2)MIN (1, −2)
GRAPH → G-Solv → MAX / MIN. You draw the function and the calculator finds its local maxima and minima. In AA it helps you check your derivative; in AI, many optimisation questions can be answered directly this way.

2. Intersection of two graphs

Y1 = e^XY2 = 4 − X² ISCT x=1.0580 y=2.8806
GRAPH → G-Solv → ISCT. The equation eˣ = 4 − x² cannot be solved by hand. In Paper 2 the expected approach is exactly this: draw both functions and read the intersections, x ≈ 1.06 and x ≈ −1.96.

3. Probabilities with the normal distribution

X ~ N(170, 8²) 160180 Ncd p = 0.7887
STAT → DIST → NORM → Ncd. Example: heights with a mean of 170 cm and a standard deviation of 8 cm. The probability of measuring between 160 and 180 cm is 0.7887, with no standardising and no tables. With InvN you go the other way: from probability to value.

4. Linear regression and correlation

hours studied → grade LinearReg ax+b a=0.8282 b=2.2630 r=0.9873
STAT → CALC → REG → X (ax+b). Enter the data in lists and you get the line and the correlation coefficient. With this data, a student who studies 5.5 hours would have an estimated grade of about 6.8. It is everyday work in Math AI and also appears in AA.

And that is just the basics. It also solves equations and systems, works with matrices, produces tables of values, calculates definite integrals and draws in 3D. In AI HL, for example, it handles matrix powers for Markov chains.

What about the fx-CG100?

It is the successor to the fx-CG50 and is also approved for the IB. If you find one at a good price, it is just as valid. Everything in this article applies to both, although the menus change a little.

Before the exam: exam mode

Before the papers, the school checks that calculators hold no programs or stored data. The fx-CG50 has an exam mode designed for this: it temporarily locks the memory and programs. Practise with the calculator in that mode at least once, so that exam day does not catch you by surprise.

What if you also sit Spain's university entrance exam?

The PAU (Spain's university entrance exam, also called Selectividad) does not allow graphing calculators. If you do the IB and plan to sit the PAU, for example its voluntary phase to raise your grade, you will also need a scientific calculator. I explain which one in which calculator to buy for Bachillerato and the PAU.

Three tips to get the most from it

  1. Use it from day one. Confidence with the menus is built in class, not in the week before the exams.
  2. Adjust the window. If you cannot see an intersection, it is probably outside the viewing window. Learn to change it with V-Window.
  3. Write down what you do. Even if the calculator gives you the result, note in the exam what you have drawn or which distribution you used. That way the examiner can award method marks.

Frequently asked questions

Is a graphing calculator compulsory in IB Maths?

Yes. The calculator papers are designed for a graphing calculator. In AA SL it is used in Paper 2, in AA HL in Papers 2 and 3, and in AI in all papers.

Can I use a calculator with CAS?

No. IB exams only allow graphing calculators without computer algebra (CAS). Check the model carefully before you buy.

Can I use the fx-CG50 for the PAU?

No. Graphing calculators are not allowed in the PAU. You will also need a scientific calculator, such as the Casio fx-991SP CW.

Is the fx-CG100 OK?

Yes. It is the successor to the fx-CG50 and is also approved for the IB.

Sources

Information updated 17 October 2026. The IB publishes its list of approved calculators every year: confirm your model with your coordinator or teacher before buying.

Keep reading
IB in Aldaia and online

Master the calculator before Paper 2.

In class we solve real exam questions with the fx-CG50, menu by menu, so that on the day of the paper you move quickly and with confidence.

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