Online Calculator
A fast basic calculator with keyboard support
Two calculators sit on this page. The basic one is a keypad with digits, four arithmetic operators, parentheses, a backspace key, clear, percent and equals — the layout a desk calculator has, and nothing more. Press equals and the exact expression you built is written into a running history of up to twelve lines that you can clear in one click. Typing works too: digits, operators, parentheses and the caret go straight in from the number row, Enter equals, Backspace deletes, Escape clears. The scientific tab takes the same engine but lets you type an expression in words instead of clicking, so `2^10 + sqrt(144)*sin(PI/6)` resolves as you finish it. There is no rounding step in the middle: results carry twelve significant digits and are trimmed only for display, so a chain of divisions does not quietly lose precision.
A clean online calculator with full keyboard support, calculation history and percent handling. Adds, subtracts, multiplies and divides instantly — no app install needed.
Private Online Calculator In Your Browser
Online Calculator is processed locally with client-side JavaScript. Your files never touch a server, and there is no queue to wait in.
How to use Online Calculator
Choose the Basic tab for the keypad, or the Scientific tab to type an expression into the Expression field.
Enter numbers and operators — digits, + − × ÷, parentheses and ^ for powers — either by clicking keys or straight from the keyboard.
Press = or Enter to evaluate. A malformed expression shows Error in the result row rather than a wrong number.
Read back the last twelve calculations in the History panel and click the ✕ to clear them.
- The percentage key divides the number you have just typed by 100, so 18% becomes 0.18 in place rather than being re-interpreted later.
- Keyboard input works from anywhere on the page except inside another text field, so digits, Enter, Backspace and Escape all map to real keys.
- Expression parsing is a proper shunting-yard implementation, which means operator precedence, right-associative powers, unary minus and implicit multiplication like 2(3+4) all behave.
- Results are rounded for display only, at twelve significant digits, so intermediate precision survives long chains.
- A shop supervisor totals a stack of invoice lines before sending the purchase order, then copies the history into the approval email.
- A developer works out a unit conversion chain such as `(0.75 * 480) / 1024` without opening a system calculator app.
- A student checking arithmetic homework runs each answer twice — once by clicking, once by typing — to catch a slip.