Simple Online Calculator
A plain four-function calculator with a keypad, percentage and sign keys, and a running history tape of everything you have worked out.
How to use it
- Click the keys or type with your keyboard — both work.
- Chaining works the way a physical calculator does: pressing an operator finishes the previous step first.
- Every completed calculation is added to the history tape below.
Examples
| 25 + 17 = | 42 |
| 200 × 15 % | 30 |
A plain four-function calculator with a keypad, running history and keyboard support — the digital equivalent of a desk calculator rather than a scientific one. It evaluates strictly left to right as each key is pressed, the same way a physical calculator does, rather than applying algebraic order of operations.
Worked example — a chained calculation
200 × 15 % then =: the percentage key divides the number on screen (200 × 15 = 3000) by 100, giving 30 — the standard way calculator percentage keys work, useful for quick discount or tip math without switching to a dedicated percentage tool.
Left-to-right vs order of operations
Typing 2 + 3 × 4 here gives 20 — (2 + 3) then × 4 — because each operator key closes out the previous step immediately, exactly like a physical desk calculator. A scientific calculator or spreadsheet would instead apply multiplication first and return 14. Neither is 'wrong'; they're different conventions, and this tool deliberately matches the simpler one.
Questions people ask
How does the percentage key work?
It divides the number on screen by 100. To take 15% of 200, enter 200 × 15 then press % and =.
Does it follow order of operations?
No, and that is deliberate — it evaluates left to right like a desk calculator. For proper precedence and brackets, use the scientific calculator.
Is anything sent to a server?
No. Every calculation runs in your browser, so nothing you type is uploaded and the page keeps working offline once it has loaded.
Last updated 22 August 2026