Basic Calculator
A simple online calculator for everyday arithmetic — add, subtract, multiply, and divide.
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.
A simple calculator is the right tool for quick, sequential arithmetic. For expressions with trigonometry, logarithms, powers, or complex operator precedence, use the scientific calculator. This basic calculator evaluates left to right, step by step — press = after each operation to chain calculations.
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.
Can I use the keyboard with this calculator?
Yes. Number keys (0–9), operator keys (+, −, *, /), Enter or = to evaluate, Backspace to delete the last digit, and Escape or Delete to clear. The calculator is fully keyboard-accessible for fast calculations without using the mouse.
How does this calculator handle order of operations?
This basic calculator evaluates left to right, one operation at a time. For example: 2 + 3 × 4 is processed as (2 + 3) × 4 = 20, not 14. For expressions that require standard mathematical precedence (BODMAS/PEMDAS), use the scientific calculator.
What is the maximum number this calculator can handle?
The calculator uses JavaScript's IEEE 754 floating-point arithmetic, which handles numbers up to about 15–17 significant digits reliably. For everyday use — bills, measurements, percentages — this limit is never a concern.
How do I calculate a square root on a basic calculator?
A basic four-function calculator does not have a dedicated square root button. To compute √n, use the engineering calculator on this site, which includes a √ button and other advanced functions.
What is the difference between C and CE on a calculator?
C (Clear) resets the entire calculation — it clears both the current number and any pending operator. CE (Clear Entry) clears only the most recent number entered but keeps the operator. In this calculator, C performs a full reset.
Can I calculate a percentage tip or discount directly?
Yes. Enter the total, press ×, type the percentage, press %. For example: 200 × 15 % = 30. For splitting bills or applying discounts, use the dedicated Tip Calculator or Discount Calculator on this site.