Basic Calculator

Everyday arithmetic, evaluated in the order you enter it

Enter a number, choose addition, subtraction, multiplication, or division, enter the next number, and press equals. This calculator performs chained operations sequentially rather than applying algebraic operator precedence. For example, entering 2 + 3 × 4 evaluates 2 + 3 first and then multiplies that result by 4. If precedence matters for a longer expression, calculate the part you need first and use its result in the next step. The display accepts up to 16 entered digits and formats completed calculations with up to 12 decimal places, which keeps ordinary results readable without implying unlimited precision.

Percentage, sign, clear, and correction controls

The percent key divides the number currently on the display by 100: entering 25 and pressing % produces 0.25. It does not automatically calculate “25 percent of” a previous number, so you can multiply the decimal result yourself when that is the intended operation. The ± key changes the sign of the displayed value. Backspace removes the last entered character, while C clears the active calculation and returns the main display to zero. Division by zero produces an error message; entering a new digit or decimal point starts a fresh calculation.

Memory and private history

Use M+ to add the displayed number to memory and M− to subtract it. MR recalls the stored memory value to the display, and MC resets memory to zero. Memory lasts only while the current page session remains open. Completed calculations are added to History when you press equals. Select a history result to place it back on the calculator, or use Clear in the History panel to remove the saved list. History is stored in your browser’s local storage on this device; Desmarto does not send it to an account or remote calculation service. Browser privacy settings can prevent that storage, but the calculator itself will still work.

Keyboard, copy, and display modes

You can type digits, the decimal point, +, -, *, /, and % from a keyboard. Enter or = completes an operation, Backspace corrects the current entry, and Escape performs the same clear action as C. Keyboard shortcuts are ignored while focus is inside another input, text area, or select menu. The copy button writes the unformatted current result to your clipboard when the browser grants access. Standard, Compact, and Desk change presentation only; they do not change the calculation. The expand control requests browser fullscreen and uses a reversible viewport-sized focus mode when element fullscreen is unavailable.

Practical checks for reliable results

Watch the expression line above the main result to confirm the pending operator and operands before pressing equals. For money, measurements, or other rounded quantities, decide the required rounding rule after calculating; the tool displays a convenient numeric result but does not choose accounting, tax, scientific, or significant-figure conventions for you. Very large inputs and repeating decimals are constrained by browser number arithmetic and the calculator’s display rounding. For records that require an audit trail, copy the result together with the values and operation you entered rather than relying only on local History.