Basic Calculator
A clean online calculator that follows the standard order of operations. Type an expression or tap the keypad — it never uses eval() and explains errors such as dividing by zero.
Result
Type an expression or use the keypad. Press = or Enter to calculate.
Recent calculations
How to use this calculator
- Type an expression in the display, for example
(12 + 8) × 3 ÷ 4, or use the on-screen keypad. - A preview result appears as you type. Press = or Enter to confirm it and add it to your recent calculations.
- After pressing =, the answer stays in the display so you can keep calculating with it.
- Use Backspace to delete the last character and Esc or AC to clear.
Formula
The calculator follows the standard order of operations: brackets first, then multiplication and division from left to right, then addition and subtraction from left to right. A leading minus sign makes a number negative, so 2 × -3 is −6.
The % key follows the convention used by most handheld calculators:
- a + b% adds b percent of a: 200 + 10% = 220.
- a − b% subtracts b percent of a: 200 − 10% = 180.
- a × b% multiplies by b ÷ 100: 200 × 10% = 20.
- On its own, b% means b ÷ 100.
Worked example
Order of operations
(12 + 8) × 3 ÷ 4
Brackets first: 12 + 8 = 20. Then left to right: 20 × 3 = 60, and 60 ÷ 4 = 15.
Adding a percentage
200 + 10% treats 10% as 10% of 200, which is 20, so the result is 220.
Assumptions and limitations
- Results are rounded to 12 significant digits to hide binary floating-point artefacts, so 0.1 + 0.2 shows 0.3.
- Very large or very small results are shown in scientific notation.
- Exponents, roots and trigonometry are not supported; this is a four-function calculator with brackets and percent.
Frequently asked questions
Why does 2 + 3 × 4 give 14 and not 20?
Multiplication is done before addition, so 3 × 4 = 12 is calculated first and then 2 is added. Use brackets — (2 + 3) × 4 — if you want 20.
What happens if I divide by zero?
Division by zero is undefined, so the calculator shows an error message instead of a misleading result such as Infinity.
Can I use my keyboard?
Yes. Type digits, + − * / ( ) % and the decimal point. Enter calculates, Backspace deletes and Esc clears.