Use a free online basic calculator for arithmetic, percentages, square roots, memory, and calculation history.
How to use this basic calculator
Type an expression with the on-screen keypad or your computer keyboard, then select the equals key or press Enter. The calculator handles addition, subtraction, multiplication, division, decimals, parentheses, percentages, square roots, squares, reciprocals, and negative numbers. Use Backspace to correct one character or AC to start over. Your previous answer remains available through the Ans key.
Order of operations
Calculations follow the standard order of operations. Parentheses are evaluated first, followed by exponents, multiplication and division, then addition and subtraction. Operations at the same level are worked from left to right. This means 2 + 3 * 4 equals 14, while (2 + 3) * 4 equals 20.
| Key | Operation | Example | Result |
|---|---|---|---|
| + | Addition | 18 + 7 | 25 |
| − | Subtraction | 18 − 7 | 11 |
| × | Multiplication | 18 × 7 | 126 |
| ÷ | Division | 18 ÷ 6 | 3 |
| √ | Square root | √81 | 9 |
| x2 | Square | 122 | 144 |
| 1/x | Reciprocal | 1/8 | 0.125 |
How the percent key works
The percent key uses familiar everyday calculator behavior. A percentage entered after addition or subtraction is based on the value before the operator: 200 + 10% returns 220, and 200 - 10% returns 180. After multiplication or division, the percentage is converted to a decimal: 200 * 10% returns 20. A percentage entered by itself is divided by 100, so 15% becomes 0.15.
Memory keys
Memory is useful when several calculations share the same subtotal. M+ adds the displayed result to memory, while M- subtracts it. MR inserts the stored number into the expression, and MC resets memory to zero. The memory indicator above the display shows whether a value is stored. Clearing the current expression does not clear memory.
Keyboard shortcuts
Number keys, parentheses, the decimal point, and the operators +, -, *, and / work directly. Press Enter to calculate, Backspace to remove the last character, and Escape to clear the current calculation. Keyboard support makes the tool practical for repeated totals and quick checks without moving between the keyboard and pointer.
Calculation history and privacy
The history panel keeps the latest ten calculations during the current page session. Select a previous row to reuse its expression, or clear the list when it is no longer needed. Inputs and calculations run locally in your browser; this calculator does not require an account or send the arithmetic expression to a calculation server.
Accuracy and limitations
Results are displayed with up to 14 significant digits. Repeating decimals and very large or very small values can be rounded for display because browser calculations use finite numeric precision. Division by zero, a square root of a negative real number, or an incomplete expression produces a clear error instead of a misleading numeric answer. For accounting, tax, engineering, or other regulated work, confirm rounding rules and requirements that apply to your use case.
Frequently asked questions
Can I use parentheses?
Yes. Parentheses change the order of operations and can be nested in ordinary arithmetic expressions.
Does AC erase calculator memory?
No. AC clears the expression and displayed answer, while Ans still recalls the last completed calculation. Use MC when you want to erase the separate memory value.
Why does 0.1 + 0.2 sometimes show rounding effects?
Computers store many decimal fractions as binary approximations. The display rounds ordinary results to a practical number of significant digits, but extremely precise decimal work may require a dedicated arbitrary-precision tool.
Is this a scientific calculator?
No. This page is designed for everyday arithmetic. Use the scientific calculator for trigonometry, logarithms, factorials, constants, and degree or radian modes.