Standard Calculator

How this calculator works

This is a standard four-function calculator, modelled on the calculator built into Windows 11. It evaluates one operation at a time in the order you type — 2 + 3 × 4 gives 20, not 14 — because each operator acts on the running total immediately. Scientific calculators apply operator precedence (multiplication before addition); a standard calculator does not.

The memory keys

The memory row works exactly like a physical desk calculator:

• MS — store the current display value in memory.
• M+ / M− — add the display value to (or subtract it from) memory.
• MR — recall the stored value to the display.
• MC — clear the memory back to zero.

Memory is handy for totalling a list of mixed calculations: work out each line, press M+ after each one, then MR for the grand total.

Percentage, square, root and reciprocal

% follows the Windows convention: mid-calculation it means "this percentage of the running total", so 200 + 10 % adds 20 (10% of 200) to give 220. x² squares the display, √x takes the square root, and 1/x gives the reciprocal — useful for converting ratios and rates.

Keyboard shortcuts

You can type directly: digits, +, -, *, /, Enter for equals, Backspace to delete a digit, Esc to clear everything, and % for percentage. Pressing = repeatedly repeats the last operation — 2 × 3 = = = gives 6, 18, 54.

History

Every completed calculation is added to the history panel on the right (up to 50 entries). Click any entry to bring its result back to the display and carry on calculating from it. History clears when you leave the page.