Java Swing Calculator

A simple desktop calculator built with Java Swing.

Features

• Add, subtract, multiply, divide
• Percent, plus/minus, backspace, clear
• Mouse and keyboard input
• Uses BigDecimal, so 0.1 + 0.2 = 0.3
• Divide-by-zero handling

Run

Requires Java 14+.

javac Calculator.java
java Calculator

Keyboard

Digits, + - * /, ., %, Enter/=, Backspace, Esc (clear).

Keyboard shortcuts use window-level bindings, so they continue to work after clicking calculator buttons or while focus is on another control.