Quick guide
How to use the basic calculator
- Enter a number using the keypad or your keyboard.
- Select an operation: add, subtract, multiply, or divide.
- Enter the next number and press equals or the Enter key.
- Use AC to reset the calculation or CE to clear only the current entry.
Included operations
What this calculator can do
Everyday arithmetic
Add, subtract, multiply, and divide positive or negative decimal numbers.
Percentages
Calculate standalone percentages or percentage changes such as 200 + 10% = 220.
Unary operations
Square a value, find its square root, or calculate its reciprocal.
Calculator memory
Store, recall, add to, or subtract from one temporary in-browser memory value.
Worked example
Calculate 18% of 250
Enter 250, press ×, enter 18, press %, then press =. The result is 45.
250 × (18 ÷ 100) = 45
Precision & limits
How results are handled
Calculations use standard browser floating-point arithmetic and display up to 14 significant digits. Very large or very small values use scientific notation. Division by zero, square roots of negative numbers, and reciprocals of zero produce a clear error instead of an invalid result.
When you enter several operations in one chain, this basic calculator evaluates each operation immediately from left to right. For example, 5 + 2 × 3 is treated as (5 + 2) × 3 and returns 21.
This calculator is suitable for general-purpose arithmetic. For accounting, regulated finance, or other work requiring exact decimal rules, use a calculator designed for that specific domain.