Free Online Basic Calculator
A simple desk calculator for everyday sums: add, subtract, multiply and divide, with memory keys and a history of your last 10 answers. Use the keypad or your keyboard.
Keyboard works too: digits, + − * /, Enter, Backspace, Esc.
History
Your last 10 calculations appear here. Click one to reuse its result.
This calculator follows the standard order of operations: multiplication and division are done before addition and subtraction. So 2 + 3 × 4 gives 14, not 20. If you want the other order, press = after 2 + 3 and then continue with × 4.
Pressing = again repeats the last operation, so 5 + 3 = = = counts up 8, 11, 14. The % key works like a desk calculator: after + or − it takes a percentage of the running total (200 + 10% becomes 200 + 20), and after × or ÷ it simply divides by 100.
Results are rounded to 12 significant digits to hide floating-point noise, so 0.1 + 0.2 shows 0.3. Need powers, roots or trig functions? Try the scientific calculator.
What does every key do?
Clear all
Erases the whole calculation and starts over. Memory and history are kept.
Clear entry
Erases only the number you are typing, so you can fix a typo without losing the rest.
Backspace
Deletes the last digit you typed. Backspace on your keyboard does the same.
Change sign
Switches the current number between positive and negative.
Percent
After + or −, finds that percent of the running total. Otherwise divides by 100.
Memory clear and recall
MR brings back the stored number; MC empties the memory.
Add to or subtract from memory
Adds the shown number to memory, or subtracts it. An M appears on the display while memory holds a value.
Equals
Shows the answer. Press it again to repeat the last operation.
Reuse an answer
Click any line in the history to put that result back on the display.
Does this calculator do multiplication before addition?
Yes. It uses the standard order of operations, so × and ÷ are worked out before + and −. 2 + 3 × 4 = 14. Press = part-way through if you want to force left-to-right order.
What happens if I divide by zero?
The display shows "Cannot divide by zero". Press any digit or C to start a new calculation — your memory and history are kept.
Which keyboard keys can I use?
Digits 0–9, the decimal point, + − * / (x also works for multiply), % for percent, Enter or = for equals, Backspace to delete a digit, Delete to clear the entry and Escape to clear everything.
Why does 0.1 + 0.2 show 0.3 here but 0.30000000000000004 elsewhere?
Computers store decimals in binary, which adds tiny rounding errors. This calculator rounds every answer to 12 significant digits so those errors never show up.
