Basic Calculator
This online basic calculator handles everyday arithmetic: addition (+), subtraction (−), multiplication (×), and division (÷). It includes a percentage key (%) for quick percent calculations and a sign toggle (±) to change positive/negative. Results are shown with up to 10 significant digits of precision. The calculator is fully keyboard-friendly — use number keys and operator keys directly.
Frequently Asked Questions
How do I calculate a percentage?
Press the number, then the % button. For example, to find 15% of 200: press 200 × 15 %, and the result is 30. Or press 15 % alone to convert 15 to 0.15.
What does the ± button do?
The ± (plus/minus) button toggles the sign of the currently displayed number. Press it to change a positive number to negative or vice versa. Useful for subtracting from a running total.
What happens when I divide by zero?
Dividing any number by zero is mathematically undefined. The calculator displays "Error" to indicate an invalid operation. Press C to clear and start a new calculation.
Is this calculator free to use?
Yes, completely free with no account needed. Works in any browser on mobile, tablet, or desktop. No download or installation required.