✨ OFFICIAL CASIO REPLICA

Scientific Calculator Online

Free online replica of the CASIO fx-991ES PLUS. All functions, same layout, no download required.

CASIO
fx-991ES PLUS
S A M H D
0
▲
◀
▶
▼

⭐ Rate This Calculator

How helpful was the CASIO fx-991ES PLUS online?

4.9 out of 5 — based on 5,000+ ratings
✨ POWERFUL FEATURES

More than just a Scientific Calculator

Toolyfi's CASIO fx-991ES PLUS replica is a complete scientific calculator experience — same buttons, same layout, same accuracy as the physical device.

🎯

Exact CASIO Replica

Same button layout, same colors, same functions as the physical fx-991ES PLUS. Builds real exam muscle memory.

All Buttons Active
📐

Full Trigonometry

sin, cos, tan, and their inverse functions. Toggle between DEG and RAD mode. Supports HYP (hyperbolic) functions via SHIFT.

DEG / RAD Mode
📊

Logs & Powers

log (base 10), ln (natural log), 10^x, e^x, x², x^y, √, ³√, and reciprocal 1/x — all in one place.

All Functions Active
⛶

Fullscreen Mode

One tap to go fullscreen — the calculator fills your entire screen. Perfect for mobile use during study sessions.

Mobile Optimized
👥 FOR EVERYONE

Who benefits from this tool?

From O-level students to engineers — everyone who uses a CASIO fx-991ES PLUS can use this free online version.

🎓

Students

Practice CASIO functions for O-levels, A-levels, FSc, and board exams without carrying your physical calculator.

📝

Exam Candidates

MDCAT, ECAT, and engineering entrance exam aspirants can practice the exact approved calculator online.

👨‍🏫

Teachers

Demonstrate calculations to students on screen during online classes without needing a document camera.

⚙️

Engineers

Quick scientific calculations during fieldwork when you don't have your physical calculator available.

❓ FAQ

Frequently Asked Questions

Everything you need to know about using the CASIO fx-991ES PLUS online.

Is this CASIO fx-991ES calculator completely free? +
Yes, 100% free. No account, no signup, no download, no payment required. Just open the page and start calculating immediately. It will always be free on Toolyfi.
How do I use sin, cos, tan? +
Enter your angle value using the number buttons, then press sin, cos, or tan. Always check your angle mode (DEG or RAD) first — tap the badge in the top-right corner of the calculator to toggle. For inverse functions (sin⁻¹, cos⁻¹, tan⁻¹), press SHIFT first, then the trig button.

What is the CASIO fx-991ES PLUS?

The CASIO fx-991ES PLUS is the world's most popular scientific calculator. Used by over 200 million students across more than 100 countries, it is the officially approved calculator for board exams, MDCAT, ECAT, O-levels, A-levels, and engineering entrance tests.

This free online version gives you the complete CASIO fx-991ES PLUS experience in your browser — same button layout, same functions, same accuracy — with no download, no installation, and no signup required.

How to Use This Online CASIO Calculator

Enter numbers using the digit buttons (0–9), use . for decimals, and the operators +, −, ×, ÷ for basic calculations. Press = to compute the result.

✅ Quick start: Click any button on the calculator above to begin. Tap the MODE button to switch angle modes. Press SHIFT for yellow secondary functions. Use Fullscreen for the best mobile experience.