with FREE Pilot Frixion Pen & refill pack (Black) worth £6.99


The UK's best selling 'Advanced' Scientific Calculator, Allowed in every UK exam where a calculator can be used. Recommended and approved for Key Stages 3, 4 and 5 (including GCSE, A-Levels, National and Higher, Junior and Leaving).

The FX-991EX uses Classwiz technology, offers a new high-resolution LC display with 192×63 pixels and a resolution that is four times higher than that of the familiar displays of the FX-ES Plus series. In addition, the new ClassWiz series boasts new hardware with a faster processor and double the memory size.

General Information
  • Solar powered with a battery back up
  • 274 Functions
  • Auto power off
  • Hard slip on case included
  • Large Natural Textbook Display (Natural-V.P.A.M.), shows mathematical expressions as they appear in textbooks
  • 192 x 63 LCD display,

Functions and Features
  • Display type: 62 * 192 FULL DOT Natural display
  • Algebraic input logic: Natural V.P.A.M.
  • Number of characters/lines: 16/1+10/1
  • Icon menu
  • Signific and function: 10+2
  • Memory
  • Repeat function
  • Variable memory: 9
  • Number of storable programs: Calc / Solv button
  • Functions: 552
  • Scientific constants: 47
  • Unit conversions: 40
  • Bracket levels: 24
  • Fraction calculations
  • Angle dimensions DEG/RAD/GRAD
  • Conversions between >DEG/>RAD/>GRAD
  • Coordinate conversion Pol
  • Trigonometric functions sin/cos/tan/sin-1/cos-1/tan-1
  • Hyperbolic functions sinh/cosh/tanh/sinh-1/cosh-1/tanh-1
  • Exponent, log, In, 10x, ex
  • Mathematical functions ?, x2, x-1, 1/x, x!, ?, xY, ?, x1/y
  • Calculations based on n (hexadecimal/decimal/binary/octal)
  • Logical operators (AND/OR/etc.)
  • Calculations in the sexagesimal system
  • Percentage calculations
  • Prime factorization
  • Technical notation ENG/ENG
  • Calculation with technical symbols
  • Calculation of complex numbers
  • Random number generator
  • Random integers
  • Base-N calculations
  • Value table


  • Free UK delivery 

  • Free 3 year guarantee included

  • Slide-on protective hard cover included

  • Allowed in every UK exam where a calculator can be used 

  • View our Model Comparison Chart to find the right calculator for you

  • With FREE Pilot Frixion Pen & refill pack (Black) worth £6.99


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Standard and Express Delivery 
options available

Click & Collect

Going to be out? Have your delivery safely sent to a local store for collection


All of our products come with at least 2 years warranty



Mainland UK
Standard: 3-5 Business days after dispatch
Express: 1-2 Business days after dispatch
(Express delivery only available for orders placed before 2.30pm – Excluding weekends & Bank Holidays)

Republic of Ireland & Channel Islands
Standard: 4-5 Business days after dispatch
Express: Not Available

Our nominated carrier is Parcel Force. Deliveries are made Monday – Friday between 9.00am – 6.00pm (excluding Bank Holidays).
If you require any further information relating to the Delivery service used, please call us at +44 (0)20 8208 9567.


If for any reason you change your mind or are not satisfied with your purchase, please return your purchase to Casio within 28 days of purchase. Please note that with the exception of faulty products, we cannot accept the return of items, which have been opened or used. This does not affect your statutory rights.

The below process should be followed:

1 - Complete the short form that accompanies your product. Please ensure that you complete all of the sections, as this will guarantee the timely processing of your return/exchange.

2 - Place your item in the original packaging along with the form. Please ensure that the product is pristine with all original manuals and tags.

3 - Send the box to us using a recorded/signed & trackable service to the address below. Please note, we cannot be held responsible for a package that has not been received by us.

4 - Return Address

Yusen Logistics Co Ltd
Casio Returns - Bay 32
Bradbourne Drive
Milton Keynes

Tel:+44(0)20 8208 9452
Email: collections@casio.co.uk

5 - Retain your tracking details, until you receive notification from Casio that your returned product has been safely received. Once received and processed, it may take up to 5-7 business days for your refund to be displayed on your payment card statement.