Basic Calculator
Free online calculator for quick math. Add, subtract, multiply, divide, percentages. Use keyboard or click. No signup.
What this calculator handles
It is a straightforward four-function calculator for the arithmetic you actually do in a browser: add, subtract, multiply, divide, and take a percentage. It also supports the keyboard — type the numbers and operators directly, press Enter to evaluate, Backspace to correct, and Escape to clear. Every result is saved to a short local history, and clicking the display copies the number.
How it works
- Order of operations is standard: multiplication and division happen before addition and subtraction, exactly as in written maths. Entering 3 + 5 × 2 gives 13, not 16.
- The percent button divides the current value by 100. Typing 50 and pressing % stores 0.5.
- Percent inside an expression is also handled: 200 × 10% evaluates as 200 × 0.1 = 20, which is what “10% of 200” means.
- Backspace removes the last character; C clears everything back to zero.
- Repeated operators replace the previous one, so a mistyped “+” followed by “×” does not break the expression.
Worked examples
| You enter | Result | Why |
|---|---|---|
| 12 × 8 = | 96 | Basic multiplication |
| 144 ÷ 12 = | 12 | Basic division |
| 3 + 5 × 2 = | 13 | Multiplication first |
| 200 × 10% = | 20 | 10% becomes 0.1 |
| 50 % | 0.5 | Percent button divides by 100 |
Common mistakes
- Expecting left-to-right maths. The calculator follows operator precedence, not the order you tap the buttons. Use brackets or break a complex sum into steps.
- Confusing the percent button with “add/subtract percent.” It converts to a decimal; for a discount, multiply the price by the percentage and subtract, or use the percentage calculator directly.
- Losing track after evaluating. Once you press equals, typing a number starts a fresh calculation. Pressing an operator continues from the result.
- Over-trusting decimal precision. Results are rounded to ten decimal places, which is fine for everyday work but not for accounting or scientific use.
Frequently asked questions
Does it follow BODMAS or PEMDAS?
Yes — both describe the same order, and the calculator applies it. Multiplication and division are evaluated before addition and subtraction, and anything you want done first should be worked out in a separate step.
How do I do a percentage increase or decrease?
For a 15% increase, multiply by 1.15; for a 15% decrease, multiply by 0.85. That is one operation instead of two, and it avoids the common error of adding and subtracting percentages that do not cancel out.
Can I use the keyboard?
Yes. Number keys, the operators, Enter to evaluate, Backspace to delete, and Escape to clear all work as long as you are not focused on another input field on the page.
Why did my answer have a long decimal?
Some divisions do not resolve to a short decimal. The calculator rounds to ten decimal places to keep the display readable; round the result yourself to the precision your task needs.
For percentage-specific questions, discounts, marks, and reverse percentages, the percentage calculator explains the three distinct formulas that most people conflate.