Calculator

Standard handles short arithmetic, Scientific evaluates expressions with powers or trigonometry, and Programmer works with integer bases and bits. Choose the mode before entering a chain of operations: Standard evaluates each step as it is entered, while Scientific applies mathematical precedence.

Start with the least complicated mode

A standard calculator is usually the right choice for a bill, a quick total or one percentage. AC resets the whole operation; C clears only the number currently being entered. The wider zero key and four-operation layout keep this mode close to a simple calculator.

• Choose Standard for addition, subtraction, multiplication, division, sign changes and percentages.
• Choose Scientific for parentheses, roots, powers, logarithms, factorials and angle functions.
• Choose Programmer when the input is an integer written in BIN, OCT, DEC or HEX.

The scientific calculator with functions such as sin, cos, tan, log, ln, √, xʸ, π and e also covers the common work expected from an engineering calculator.

The percent key follows the operator

In Standard mode, addition and subtraction use the first number as the percentage base. Enter 500 - 20 % to show 100, then press = to get 400. With multiplication or division, the percentage is treated as a ratio: 50 × 10 % returns 5, while 50 ÷ 10 % returns 500. Pressing 20 % by itself produces 0.2. Scientific mode behaves differently: % divides the entire expression by 100, so (500 - 20) becomes 4.8.

A dedicated percentage tool is clearer for reverse percentages, percentage change and several discounts in sequence. The percent key here is meant for the short pattern familiar from a handheld calculator.

Scientific results depend on order and angle unit

The scientific calculator follows mathematical precedence. It reads 2 + 3 × 4 as 14, but (2 + 3) × 4 as 20. Exponents associate from the right, so 2^3^2 is 512; negative exponents such as 2^-2 are accepted as well.

A function key uses the complete expression on the display. Type 2 + 3 and then press √ to calculate the square root of 5, rather than the square root of the first number. Adding π or e after a number inserts multiplication automatically.

Select DEG when an angle is given in degrees and RAD when it is given in radians. In DEG, sin(30) is 0.5. tan(90°), division by zero and the square root of a negative number return an error. Factorial accepts whole numbers from 0 through 20, rather than silently rounding a decimal input.

Standard and Scientific use JavaScript Number arithmetic, not arbitrary-precision decimals. Most answers show up to 12 decimal places; very small or large values use scientific notation. Continuing from an answer uses the rounded displayed value. Integers above 9,007,199,254,740,991 are not all exactly representable in these modes; Programmer uses BigInt for integer arithmetic.

Programmer arithmetic and bit operations are different

Changing BIN, OCT, DEC or HEX keeps the integer value and redraws it in all four bases. Regular arithmetic uses exact integer values within the input length shown by the keypad; division truncates towards zero: -7 / 2 gives -3. AND, OR, XOR, NOT and the two shift buttons use a 32-bit unsigned bit pattern. That detail explains why NOT can produce a large positive decimal value.

Keyboard input and saved history

Digits and +, -, *, / can be typed directly. Enter or = evaluates, Escape clears, and Backspace removes the latest character; Scientific also accepts typed parentheses. Either the decimal point or comma key enters a decimal point on screen. The latest 20 Standard results remain in the history panel, where any result can start the next operation.

Expressions are calculated in the browser, not sent to the server by the calculator. The Standard history stays in that browser’s local storage. Clear in the history panel deletes saved entries, not the number still on screen; use AC for that. If browser storage is blocked, calculations still work but history may not persist.