The Casio fx-991EX is one of the most advanced scientific calculators globally, renowned for its ClassWiz high-resolution LCD, over 552 functions, and excellent performance in science, engineering, and education. Our online replica lets you:
Perform complex scientific, trigonometric, and statistical calculations just like the real calculator
Switch between DEG/RAD modes for angle calculations
Work with exponents, logarithms, factorials, powers, roots, and constants (π, e)
No installation required – perfect for homework, classroom, or professional use from any device. Note: For more advanced settings and tables, always refer to your physical Casio calculator's manual.
Why use our online fx-991EX calculator?
Free & Easy Access: No login or registration required.
Responsive Design: Optimized for both desktop and mobile.
Educational Resource: Great for practicing functions before exams!
About Casio fx-991EX Online Calculator
This web app was created to bring the powerful capabilities of the Casio fx-991EX into your browser – free, accessible, and with no need to purchase extra hardware. Our mission is to support students, teachers, professionals, and enthusiasts who need a reliable scientific calculator anytime, anywhere.
Features
552+ common scientific functions, including trigonometry, logarithms, factorial, fractions, and more
Shift and ALPHA key simulation for extended functions
Persistent calculation history with easy copy
Fully responsive design for desktop and mobile
SEO-optimized, privacy-respecting, and open access
Our Vision
We believe every student and professional deserves high-quality calculation tools, regardless of device or income. This project aims to bridge the accessibility gap by providing a digital replica of the most popular scientific calculator – including clear explanations of major functions and efficient technical support.
Have suggestions or want to contribute? Visit our Contact page!
Blog & Learning Hub
How to Use the Casio fx-991EX for Exam Success
Posted on June 16, 2024
Learn the quickest ways to use features like TRIG, LOG, and complex calculations on your Casio fx-991EX, including advice for engineering and STEM exams. Our online calculator lets you practice ahead of time. Try now →
Switching between DEG, RAD, and GRAD
Posted on June 10, 2024
Struggling with angle units? The fx-991EX makes it easy to switch modes. Click DEG or RAD to toggle instantly, and always check your mode before starting trig calculations to avoid common mistakes.
Why the fx-991EX is the Best Exam Calculator
Posted on June 1, 2024
It's exam-approved worldwide, supports fraction and matrix calculations, and its interface is simple. Discover why our online version is a top choice for students in math, physics, chemistry, and more.
Contact Us
Do you have feedback, feature requests, or partnership queries? Reach out using the form below, and our team will respond promptly!
We respect your privacy. This website does not collect personal data or track users. Here's how we maintain your confidentiality:
No Analytics or Cookies: This site doesn't use analytics tools, cookies, or tracking pixels.
Form Data: Messages sent via our Contact form are not stored nor used for marketing. We never share your information.
Open Source: All calculator logic runs client-side, ensuring full transparency.
Third-Party Links
Our website may link to external resources (e.g., Casio's official site). We are not responsible for their content or privacy practices.
Children's Privacy
This site is safe for students of all ages. We do not knowingly collect information from children under 13.
Terms & Conditions
1. Acceptance of Terms
By using the Casio fx-991EX Online Calculator, you agree to these terms and all applicable laws and regulations. If you disagree with any part of these terms, discontinue using the site.
2. Use License
Permission is granted to use the calculator for personal or educational purposes only. Commercial use, resale, or hosting without permission is prohibited.
3. Disclaimer
All content is provided "as is". We make no warranties regarding accuracy, reliability, or fitness for a particular purpose. Always verify results for critical computations.
4. Intellectual Property Rights
This site is not affiliated with Casio. All trademarks remain the property of their respective owners.
5. Governing Law
These terms shall be governed by the laws of your jurisdiction.