How to use this calculator
- Enter a number using the keypad or your keyboard.
- Choose an arithmetic operator.
- Enter the next number and press equals.
- Use AC to reset or Backspace to correct the current number.
Supported calculations
- Addition (+), subtraction (−), multiplication (×) and division (÷).
- Decimal numbers and positive/negative values.
- Percentage conversion. For example, 25% becomes 0.25.
- Keyboard and touch-screen input.
Basic arithmetic formulas
Addition: a + b
Subtraction: a − b
Multiplication: a × b
Division: a ÷ b (b must not be zero)
Accuracy and limitations
Results use JavaScript number arithmetic and are displayed with practical precision. The calculator is intended for everyday arithmetic. For tax, lending, investment, accounting or regulated decisions, verify figures with the relevant official source or a qualified professional.
Worked examples
Use these examples to check the calculator and understand the result before using it for your own figures:
- Addition: 125 + 75 = 200. This combines two amounts into one total.
- Subtraction: 500 − 135 = 365. This finds the difference between two values.
- Multiplication: 24 × 6 = 144. This is useful for repeated quantities, such as the cost of six items priced at 24 each.
- Division: 960 ÷ 8 = 120. This splits a total into eight equal parts. Division by zero is undefined.
- Percentage: 15% of 800 = 120. Convert the percentage to a decimal (15 ÷ 100 = 0.15), then multiply 800 × 0.15.
- Decimals: 12.5 + 2.75 = 15.25. Enter the decimal point using the keypad or keyboard.
Tips for reliable results
- Check the digits and decimal point before pressing equals.
- For a multi-step calculation, split the work into smaller steps and note each intermediate result.
- For a percentage of an amount, divide the percentage by 100 and multiply by the amount.
- Use Backspace to correct the current entry or AC to clear the calculator and begin again.
- For important financial or business calculations, independently verify the inputs and final result.
Frequently asked questions
Can I use this basic calculator on a phone?
Yes. The keypad is designed for touch input on phones and tablets, and the supported keyboard shortcuts can be used on compatible physical keyboards.
Does the calculator support decimal numbers?
Yes. Enter a decimal point as part of a number, such as 12.5 or 0.75. The displayed result is formatted for practical everyday use.
How do I calculate a percentage?
To find 15% of 800, calculate 800 × 15 ÷ 100. The result is 120. For a different percentage, replace 15 and 800 with your own values.
Why should I verify an important result?
Displayed results depend on the values entered and ordinary JavaScript number arithmetic. For tax, loan, accounting or other consequential decisions, check the assumptions and verify the calculation against an authoritative source.
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