Casio fx-991EX Scientific Calculator


Casio FX-991EX Scientific Calculator with High-Resolution LCD

The New Classroom Standard With High-resolution LCD Technology, making it easier to view numerical formulas and symbols.


  • High Resolution Display to view more data like spreadsheets & 4x4 matrix calculations
  • Natural Text book display - symbols and numbers appear just as they do in textbook
  • QR code function enables access to graphical representations and on-line manual
  • 552 functions with unit conversions and scientific constants
  • Calculations with Engineering symbols
  • Numeric Integration/Differentiation
  • Simultaneous and Polynomial Solver
  • Equation and system solver up to 4 variables
  • Complex number calculations
  • Probability distribution list or varible input (Binomial PD-CD, Normal PD-CD, Poisson PD-CD)
  • Statistic editor enables easy input & correction of data
  • Solar Powered with Battery Backup (LR44 Button Cell Battery Included)

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Powerful and Easy to Use Casio FX-991EX Scientific Calculator

A new high-performance scientific with high resolution display increasing the amount of information displayed and super-fast calculation speed for high-stakes testing or for performing the most advanced mathematics.

Casio FX-991EX Scientific Calculator provide high resolution LCD screen allows more information for applications like Spreadsheets and 4X4 matrix calculations. This calculator has a comprehensive set of advanced calculations for integration and differential calculus, along with vector and inequality calculations. For the middle and high school grades, we’ve incorporated basic spreadsheet functionality, ratio and statistical functionality, down to ratio calculation and prime factorization.

No matter what the need, this scientific calculator can do it all

Need graphical representation for data generated by the fx-991EX - no problem! Generate a QR code for your problem, scan the code and immediately see a graphical representation of your data; within a classroom, students can see their collective data in real time with other students.

Main functions

  • Variables list
  • Prime factorization
  • Random integers
  • Coordinate transformation
  • Power calculation
  • Trigonometry
  • Fraction calculations
  • Combination and permutation
  • 9 variables
  • Statistics (List-based STAT data editor, Standard deviation, regression analysis, Statistics list)
  • Table function
  • UNDO
  • Digit separator
  • Multiline display

Additional functions

  • Spreadsheet calculations
  • Integration calculations
  • Differential calculations
  • CALC function
  • SOLVE function
  • Complex number calculations
  • Base-n calculation
  • Equation calculations
  • Matrix calculations
  • Vector calculations
  • Scientific constants
  • Metric conversions
  • Advanced statistical distribution calculations
  • Inequality calculations
  • Ratio calculations
  • QR Code
  • Engineering symbol calculations

User Reviews

User: Terry Yan
User Rating: ★★★★★
I bought this scientific calculator after I lost my fx-82es, the one that has accompanying me for more than five years. This 991ex, is so much more powerful than my previous one, and its price is really reasonable. I would say it's worth buying.


User: Jeffrey
User Rating: ★★★★★
BEST CALCULATOR EVER!!!! I had a Ti-84 for years during my studies and now replaced it by the Casio FX-991-EX. You can view all of its functions on the Casio website. This calculator is great for any calculus courses or if you are in engineering. I have switched calculator for my engineering studies and do not regret it all. I enjoy this calculator and is very easy to use. This Casio FX-991EX scientific calculator is a must have. The best ever.


Udser: Brett H.
User Rating: ★★★★★
Was super exited to find out there was a new approved calculator for the NCEES Exams. Read up and watched a bunch of videos on Casios website and was please to see it was a higher resolution screen compared to most of the NCEES approved calculators. The calculator was very intuitive and the solver function worked great. Would recommend this calculator to anyone taking the PE exam. Definitely helps to have the extra digits on the screen. Casio definitely nailed it with this calculator.


User: B. Bergman
User Rating: ★★★★★
Pretty sweet calculator, and this coming from a dedicated HP user (and collector). This one has a great collection of features and capabilities, a really nice (new) display, and the calculator case itself is much more attractive. My kids abandoned their old calculators (which were prior versions of the same model) for this in a heartbeat. The QR code feature is really sweet -- very surprised by that!


User: yabusa
User Rating: ★★★★★
Amazing build quality and finish. Amazing scientific calculator. Very light weight and good quality. Comes with a hard cover as most calculators these days. Key reason I selected this one over others was for Logarithmic functions. You can input the base of the logarithm, which very few have this function. Very happy with options and features. Large solar cell as well.