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Online calculator

Calculator

Free online calculator for everyday arithmetic with keyboard support.

Use the keypad or keyboard. Press Enter for equals, Escape to clear, and Backspace to delete.

Result

0

Calculation history

Recent calculations appear here during this session.

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Quick help

Introduction

This online calculator performs common arithmetic quickly in a clean, keyboard-friendly interface. It supports addition, subtraction, multiplication, division, decimals, percentages, clear, and backspace.

How to use the calculator

Enter numbers and operators with the keypad or keyboard, then press equals or Enter to calculate. Use clear to reset the expression and backspace to remove the last character.

Supported operations

The calculator supports controlled arithmetic expressions using numbers, decimals, parentheses, plus, minus, multiply, divide, and percent. Unsupported characters are rejected before calculation.

Calculator terms

Expression

The numbers and operators entered into the calculator.

Result

The evaluated value of a valid expression.

Keyboard input

Digits, operators, Enter, Backspace, Escape, and Delete are supported.

Supported operations and keyboard shortcuts

Addition

a + b

Addition combines two values.

Subtraction

a - b

Subtraction finds the difference between two values.

Multiplication

a x b

Multiplication repeats or scales a value.

Division

a / b

Division splits one value by another.

Percentage

a% = a / 100

For example, 50% is treated as 0.5, so 200 x 10% equals 20.

Basic arithmetic examples

Addition

  1. Enter 12 + 8.
  2. Press equals.
  3. Result is 20.

Subtraction

  1. Enter 25 - 9.
  2. Press equals.
  3. Result is 16.

Multiplication

  1. Enter 6 x 7.
  2. Press equals.
  3. Result is 42.

Division

  1. Enter 84 / 4.
  2. Press equals.
  3. Result is 21.

Decimals

  1. Enter 2.5 + 1.25.
  2. Press equals.
  3. Result is 3.75.

Percentage

  1. Enter 200 x 10%.
  2. Press equals.
  3. Result is 20.

Common mistakes

Dividing by zero

Division by zero is invalid and returns an accessible error.

Incomplete expressions

Expressions ending in an operator need another number before calculation.

Unsupported characters

Only arithmetic symbols, numbers, decimals, parentheses, and percent are accepted.

Percentage assumptions

This calculator treats percent as a number divided by 100.

Too many decimal points

Each number can include only one decimal point.

FAQs

Is this calculator free?
Yes. This online calculator is free to use.
Can I use keyboard input?
Yes. Use digits, operators, Enter, Backspace, Escape, and Delete.
Does it support decimals?
Yes. Decimal numbers are supported.
Does it support percentages?
Yes. Percent converts a number into a value divided by 100.
Does it use JavaScript eval?
No. It uses a controlled arithmetic parser and evaluator.
Can I divide by zero?
No. Division by zero is rejected.
Does it support parentheses?
Yes. Parentheses can group operations.
What does clear do?
Clear resets the expression, result, and error state.
What does backspace do?
Backspace removes the last character from the expression.
What operations are supported?
Addition, subtraction, multiplication, division, percentage, decimals, and parentheses.
Is this a scientific calculator?
No. This page is a general-purpose arithmetic calculator.
Can I see calculation history?
A lightweight history placeholder is included for recent calculations.
Is the result announced to screen readers?
Yes. Result updates use an aria-live region.
Can I use it on mobile?
Yes. The keypad is designed for mobile and desktop layouts.
What happens for invalid input?
The calculator shows an accessible error message and does not evaluate unsafe input.

References

Related calculators

Last updated and version history

Last updated: 2026-07-04

  • 1.0.0 (2026-07-04): Initial production release with safe arithmetic evaluation, keypad, keyboard input, and accessible results.