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Free scientific calculator online
Scientific Calculator Casio Online
Use a free Casio-style scientific calculator online for trigonometry, logarithms, powers, roots, scientific notation, and everyday math.
CASIO STYLEfx-991ES PLUS Inspired
DEGREADY
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Features
Core scientific functions
Trig modes
Switch between DEG and RAD for sine, cosine, tangent, and inverse trigonometric functions.
History and keyboard
Reuse Ans, restore recent calculations from local history, and type common keys from a desktop keyboard.
How to use
Enter, calculate, and reuse results
Enter an expression
Tap keys or use the keyboard to enter numbers, operators, functions, and parentheses.
Choose DEG or RAD
Press MODE to switch the angle mode before calculating trigonometric expressions.
Press equals
The result appears on the LCD-style display and is saved to recent history for quick reuse.
Online Scientific Calculator
A Fast Casio-Style Scientific Calculator for Everyday Math
Built for practical calculations
This scientific calculator Casio online style tool gives students, teachers, engineers, and everyday problem solvers a familiar layout in the browser. It supports arithmetic, powers, roots, logarithms, trigonometric functions, inverse trigonometric functions, constants, percentages, Ans recall, and scientific notation without requiring an account or app install.
The visual interface is inspired by classic black scientific calculators, with a dark display, rounded keys, orange clear buttons, purple accent controls, and compact yellow function labels. It is a casio-style scientific calculator experience, but it is an independent website and not an official Casio product.
Useful for school and engineering work
You can use this free scientific calculator online for trigonometry homework, logarithm practice, physics formulas, quick engineering estimates, percentage checks, and everyday arithmetic. DEG and RAD modes make it easier to match the angle units used by a textbook, class, spreadsheet, or programming environment.
The calculator accepts expressions such as sin(30), log(100), ln(e), √(81), 2^10, and 1e6. Results are formatted to stay readable, and syntax or math errors are shown on the display instead of breaking the page.
Mobile-friendly 991-style layout
The 991-style calculator online layout is designed for phones, tablets, and desktops. Large touch targets make it usable on mobile, while keyboard input helps desktop users enter numbers and operators quickly. The recent history panel keeps the last calculations in browser localStorage so a refresh does not erase your current work.
This engineering calculator online MVP focuses on reliable core functions first. Matrix tools, equation solving, derivatives, integrals, step-by-step explanations, and multilingual pages are good future additions, but the first version prioritizes a clean calculator, readable pages, and a deployable Vercel setup.
FAQ
Common Questions
Is this an official Casio calculator?
No. This is an independent web calculator with a Casio-style scientific calculator interface. It is not affiliated with or endorsed by Casio.
Is this calculator free?
Yes. The MVP is a free scientific calculator online that runs in your browser without an account or subscription.
Does it work on mobile?
Yes. The calculator is designed to fit phone, tablet, and desktop screens with touch-friendly keys.
What is DEG/RAD mode?
DEG means trigonometric input and inverse output use degrees. RAD means the same functions use radians, which is common in higher math and programming.
Disclaimer: This website is an independent calculator tool and is not affiliated with or endorsed by Casio. Casio is a trademark of its respective owner.