Scientific Calculator for 991ES, 991EX and 991CW

CalcES is a free scientific calculator for the calculations that outgrow a phone's basic keypad. Enter fractions, roots, logarithms and trigonometry in textbook-style notation. Choose an ES PLUS, EX or ClassWiz CW-style keypad when you want to practise the sequence you use on a matching handheld.

From a fraction to a longer problem

Start with an expression and keep working as the question changes. Whether you call it a scientific calculator or calculator scientific, it gives you more room than a basic phone widget. A fraction can stay exact until the final line; then you can view a decimal if the assignment calls for one. Choose degrees or radians before evaluating a trigonometric expression. For algebra, calculate roots of an equation or work through a system of equations. The quadratic equations guide covers the method behind a common school problem, while the trigonometric identities guide helps when the answer needs a reason as well as a number.

Calculus, matrices and complex numbers are here for later coursework and technical work. Enter a derivative at a point, a definite integral or a limit. Build a matrix to calculate its determinant or inverse, and use row reduction when you need to inspect a system. In electrical or engineering calculations, switch between rectangular and polar complex forms, or use engineering notation for large and small quantities.

Which 991 or 570 do you mean?

For Casio 991 online practice, first match your 991ES, 991EX or ClassWiz calculator to its keypad family. CalcES has an ES PLUS-style keypad for the fx-991ES PLUS and fx-570ES PLUS, an EX-style keypad for the fx-991EX and fx-570EX, and a ClassWiz CW-style keypad for the fx-991CW. With the ClassWiz CW board, the familiar keys sit in the familiar layout, so you can enter calculations the way you do on an fx-991CW.

The same supported families use local names elsewhere: fx-82ZA PLUS II in South Africa; fx-82AU PLUS II and fx-8200AU in Australia and New Zealand; fx-97SG X and fx-97SG CW in Singapore; fx-83GTCW in the United Kingdom; and fx-991ES PLUS in Nepal, Egypt and Pakistan. Select the family you know and practise with the key order used on that handheld.

CalcES is an independent MathDa product. It is not affiliated with or endorsed by Casio. Casio, ClassWiz and the model names here are trademarks of their respective owners.

Keep the working with the answer

If you arrived looking for a calc solver or need the steps behind a supported calculation, open the built-in Tales Math Solver from the result. Used as a calculator simulator, CalcES keeps the keypad and calculation history together while you practise. It appears beside the keypad on larger screens or as a sheet on a phone. If a function is easier to understand as a picture, use the Graph tab or the graphing calculator. You can plot a function, equation or inequality and inspect where curves cross.

A paper problem can be photographed, uploaded or drawn into the calculator. Check the editable expression before asking for the result. You can then return to a previous line in the history, store values for a later calculation, or adjust the display convention for decimal separators and digit grouping. The calculator is a place to keep working, not just a box for one answer.

Frequently asked questions

Does CalcES work like an fx-991ES PLUS, fx-991EX or fx-991CW?

CalcES supports ES PLUS, EX and CW-style keypads with the familiar keys and calculations for each family. Choose the family your handheld belongs to and practise in the layout you know. CalcES is independent and is not affiliated with Casio.

Can I graph a function here?

Yes. The Graph tab plots functions, equations and inequalities. You can tap a curve to inspect crossings and intersections.

Does the calculator show steps?

Tales Math Solver can open from a result for supported step-by-step problems. Some calculations return an answer without a worked explanation.

Is CalcES free, and do I need to install anything?

CalcES is free in your browser without an account or download. Sign in only if you want your calculation history on another device.

Can I use the website in an exam room?

No. Practise here beforehand and follow the exam's current equipment rules for the room.

About CalcES

CalcES is made by MathDa for study and everyday mathematical work. Verify critical results and required rounding with the source material for your task.