Calculator Extension – Featuring History, Shortcuts & Themes

A Smart, Efficient, and User-Friendly Arithmetic Tool. Whether you're performing quick day-to-day calculations or working with complex expressions, the Calculator Extension delivers speed, precision, and convenience — all in one clean interface.

Enter. Evaluate. Reuse.

The Calculator Extension is built with usability in mind. The entire process — from entering your expression to reviewing past results — follows a logical, step-by-step flow designed to keep you focused and efficient.

• Input with Ease: Type your expressions directly into the calculator using either the keyboard or on-screen buttons. It supports all essential arithmetic operations, including addition, subtraction, multiplication, division, percentage, and exponentiation — while strictly following operator precedence. Start with a minus sign for negative numbers and write naturally, the calculator handles it all.
• Instant, Accurate Results: Get your result the moment you hit Enter or click the "=" button. The calculator intelligently removes trailing operators to prevent errors, ensuring that every calculation is handled with clarity and accuracy.
• Never Lose Track: Every step counts — up to the last 100, in fact. The built-in history lets you revisit and reuse past calculations. With a single click, you can load any previous entry for quick tweaks or re-evaluation.

Built for the Way You Work

Go beyond simple calculations with thoughtful features that adapt to your workflow. Whether you rely on keyboard shortcuts, want a consistent visual style, or need to revisit past results, this calculator is built to support the way you think and operate — smoothly and efficiently.

Smart History for Smarter Workflow:

Forget retyping. With calculation history always at your fingertips, repeating or editing a previous operation takes just a single click.

Keyboard Shortcuts that Keep You in Flow:

Navigate and calculate quickly with full keyboard support. Enter numbers, apply operators, delete digits, or clear entries — all without lifting your fingers from the keyboard.

Themes That Fit Your Style:

Whether you prefer the clean look of Light Mode or the sleek focus of Dark Mode, switch themes instantly and enjoy a consistent experience across the entire interface — including the display, buttons, and history panel.

Symbol Flexibility for Every Preference:

Use symbols that match your context. Switch between traditional operators (×, ÷, +, −) for familiarity or digital ones (*, /, +, -) for coding and technical precision. Your chosen style applies globally across the app.

Offline-Ready and Always Available:

No connection? No problem. This calculator works fully offline, so you're never left without your essential tool.

Why It Stands Out

Whether you're crunching numbers for a quick estimate or logging detailed calculations, this extension is built to streamline your workflow with precision and ease:

• Supports all core operations: +, −, ×, ÷, %, ^ — with strict adherence to standard math precedence.
• Stores up to 100 previous calculations for instant retrieval and editing.
• Offers keyboard shortcuts for speed and accessibility.
• Lets you switch between Light and Dark themes instantly.
• Provides global toggle for operator symbol styles (traditional vs digital).
• Works seamlessly offline, anytime you need it.

Whether you're offline on the go or multitasking at your desk, this calculator extension ensures speed, clarity, and convenience are always within reach.

Do the Math — Your Way

Fast, reliable, and thoughtfully designed — the Calculator Extension is your perfect number-crunching companion, built to keep up with you every step of the way.

Engineering Perspective

The Calculator Extension is engineered as a lightweight, offline-first browser tool with a strong emphasis on correctness, usability, and predictable behavior. While the problem domain is intentionally simple, the implementation focuses on delivering a reliable calculation engine and a polished day-to-day user experience within a Chrome extension environment.

Technical Overview

• Frontend: Vanilla JavaScript with a structured, state-driven UI model
• Styling: Custom CSS with full Light and Dark theme support
• Platform: Chrome Extensions API
• Calculation Engine: Custom-built arithmetic parser and evaluator
• Persistence: Local storage–based history retention
• Runtime: Fully offline-capable after installation

Technology Stack

JavaScript

HTML

CSS

Chrome Extensions API

Key Engineering Decisions

All calculations are performed using a custom-built arithmetic engine rather than relying on external libraries or APIs. This ensures full control over operator precedence, edge-case handling, and expression normalization, resulting in consistent and predictable output across all supported operations.

The calculator follows a strict input sanitation and evaluation flow. Trailing operators are removed automatically, negative numbers are handled explicitly, and expressions are evaluated only when they reach a valid state. This minimizes runtime errors and improves overall user trust in the results.

Calculation history is capped at the most recent 100 entries and stored locally. This limit prevents uncontrolled growth while still supporting practical reuse and iteration of previous calculations without performance degradation.

Keyboard interaction is treated as a first-class input method. All core operations, and edits are accessible through keyboard shortcuts, allowing users to work efficiently without switching input modes.

Challenges & Solutions

• Correct operator precedence: A custom evaluation flow ensures that arithmetic expressions follow standard mathematical precedence, delivering mathematically correct results across mixed operators and complex inputs.
• History usability without complexity: Instead of storing raw results only, full expressions are preserved, allowing users to reload and modify previous calculations with a single click.
• Consistent theming: Light and Dark modes are implemented across all UI surfaces—including display, keypad, and history—ensuring visual consistency and reduced eye strain.

What This Demonstrates

• Strong attention to correctness and predictable behavior in core logic
• User-focused enhancements layered onto a simple problem space
• Clean separation between calculation logic and UI concerns
• Practical experience building offline-first Chrome extensions