Basic Calculator
Keyboard: digits, + − * / ^ ( ) ! %, Enter for =, Backspace, Esc to clear.
A free basic calculator for quick everyday arithmetic. Click the keys or type on your keyboard to add, subtract, multiply and divide, then press = or Enter.
Type or click a number, choose an operation, enter the second number and press equals. You can chain as many operations as you like before pressing equals, for example 25 + 17 − 8 × 2. The calculator respects the usual order of operations, so multiplication and division are done before addition and subtraction; that example gives 26, not 52. Use parentheses from the keyboard if you need a different order.
After a result appears, pressing an operator continues from it while pressing a digit starts a fresh calculation. The line above the display shows the calculation you just finished, which makes it easy to spot a mistyped number. Back removes the last character, and AC clears the display without erasing memory.
Memory keys let you keep a running total while you work through several separate calculations. M+ evaluates what is on the display and adds it to memory; M− subtracts it. MR inserts the stored value into the current calculation, and a small M indicator on the display shows what memory holds. Memory survives AC, so you can clear the display and keep going.
Ans works differently: it always refers to the most recent result. That is handy when the next step builds on the previous one, such as working out a price, then the tax on that price, then the total.
The % key divides the number before it by 100, so 200 × 15% gives 30, the usual way to find a percentage of an amount. To add a percentage, multiply by one plus the rate: 80 × 1.07 adds 7% to 80. The ± key flips the sign of the number you are typing, and RND inserts a random number between 0 and 1.
EXP enters numbers in scientific notation: 3 EXP 8 is 3 × 10⁸. Very large or very small results are shown in the same notation, for example 1.2E+20. The display keeps up to 15 significant digits and hides the rounding noise that computers produce with decimals, so 0.1 + 0.2 shows as 0.3.
Every key has a keyboard equivalent. Use the number row or keypad for digits and the decimal point, and + − * / for the four operations. Enter or = evaluates, Backspace deletes, and Escape or Delete clears. Keyboard input is ignored while you are typing in another field on the page, such as the site search box.
Frequently asked questions
Does the calculator follow the order of operations?
Yes. Multiplication and division are done before addition and subtraction, so 2 + 3 × 4 = 14. Use parentheses for a different order.
How do I calculate a percentage of a number?
Multiply the number by the percentage and press %. For example 250 × 12 % gives 30.
What do M+, M− and MR do?
M+ adds the current result to memory, M− subtracts it, and MR inserts the stored value. Memory is kept until you reload the page.
What is the difference between AC and Back?
Back deletes the last character you entered. AC clears the whole display but keeps memory and the last answer.
Updated by Calculator.hair. How we build and check our calculators