4 Function Calculator
A simple online calculator with the four basic functions — addition, subtraction, multiplication and division — plus percent, square root, sign change and memory keys. Use the on-screen buttons or your keyboard (numbers, + − * /, Enter, Backspace, Esc).
Worked example
Example: add 8% tax to $45.50
- Type 45.5 × 1.08
- Press =
49.14
Formula
Order of operations: × and ÷ before + and −
This calculator evaluates the whole expression with standard precedence, so 2 + 3 × 4 = 14 (not 20, as on some cheap pocket calculators). Use parentheses on the scientific calculator for more control.
Frequently asked questions
What is a 4-function calculator?
A basic calculator limited to addition, subtraction, multiplication and division, often with percent and memory. Many standardized tests (including some state exams) allow only this type.
How does the % key work?
It divides the current number by 100, so 200 × 15% gives 30.
Can I use my keyboard?
Yes: digits, the decimal point, + − * /, Enter or = to calculate, Backspace to delete and Esc to clear.
Last reviewed October 17, 2026 · Calculations run in your browser; nothing you enter is sent to a server.