Calculator
A fully functional calculator built with vanilla HTML, CSS, and JavaScript.
JavaScriptHTMLCSS
Published Fri Sep 25 2026
A simple calculator built from scratch using vanilla JavaScript — no frameworks, no libraries.
Features
- Basic operations: addition, subtraction, multiplication, division
- Percentage and delete buttons
- Handles division by zero gracefully
- Rounds floating-point precision issues (0.1 + 0.2 = 0.3, not 0.30000000000000004)
- Clean dark UI with a modern color palette
What I Learned
- DOM manipulation with
querySelectorAllandaddEventListener - State management using JavaScript variables
- Using
data-*attributes to clean up event handling - Handling edge cases and floating-point math