T991 Scientific Calculator

Jack Yu(于)

About this app

T991 Scientific Calculator is the calculator for students and engineering student. Emulates CASIO fx-991es physical calculator.

Features:

1.percentage, powers, roots, trigonometric, logarithms calculator.

2.linear algebra, calculus, complex numbers, display result in rectangular and polar coordinates, matrix and vector.

3.equation solver can solve quadratic, cubic equations, systems of equations.

4.support undo, history, copy/paste

Random integers
Fraction calculations
Combination and permutation
Statistics (List-based STAT data editor, standard deviation, regression analysis)
9 variables
Table function
Equation calculations
Integration/differential calculations
Matrix calculations
Vector calculations
Complex number calculations
CALC function
SOLVE function
Base-n calculation

Ratings and reviews

This is a truly excellent calculator, far better than the ad-filled popular alternatives. I just have one small request: it would be great if users could set the default to standard notation. For example, inputting 1 ÷ 2 would automatically display 1/2, and cos 30° would show √3/2. While it seems this is the intended behavior, in practice it doesn’t work that way, you currently have to press Format each time.

Original review on 15/1/2025: Good calculator, supposedly a close resemblance on Casio Classwiz, but with bugs. Found this bug just after trying for a short while: 1. Can never make the default Ans in surd form, despite changing in setting 2. √(72*75/288) gives Maths Error. Updated review on 23/4/2026: After more than a year, the bugs mentioned earlier still exists. Developer did not bother to fix the bug. Saw a bug fix released mid 2025, but these bugs are not fixed.

Very good, good, good calculator app.. I am very happy that I can learn how to use CW calculator by using it. But some features are not working or some features are not added.

What’s new

fix bugs