A worked scratchpad
Let the expression show your reasoning
Write a calculation in one line, then use parentheses to make the grouping explicit. These examples are evaluated by the same expression engine used in the calculator.
2 + 3 * 4 = 14
Multiply 3 by 4, then add 2.
(2 + 3) * 4 = 20
Add inside the brackets first.
2 ^ 10 = 1024
Ten factors of 2.
sin(30 * pi / 180) = 0.5
Convert 30 degrees to radians before taking sine.
17 % 5 = 2
The remainder after division, not a percentage.
The angle matters
The trigonometric functions use radians. There is no degree-mode switch. To use an angle in degrees, multiply it by pi / 180 inside the function. Inverse trigonometric functions also return radians; multiply their result by 180 / pi if you need degrees.
log(100) uses base 10 and gives 2. ln(e) uses the natural logarithm and gives 1. Include the function’s parentheses so its argument is clear.
Repair the expression before starting over
Use backspace to remove the last character, or AC to clear the calculation. Check unmatched parentheses, a missing multiplication sign, and misspelled function names. Write 2 * (3 + 4) rather than relying on implied multiplication.
For negative bases, write the intended grouping explicitly: (-2) ^ 2 squares negative two. To negate a square, write -(2 ^ 2). This avoids ambiguity when moving an expression between calculators.
Know what the result represents
This calculator works with real-number JavaScript arithmetic. A square root of a negative number has no real result here, and dividing by zero is not a finite answer. Decimal calculations can contain tiny floating-point rounding differences; retain enough precision for intermediate work and round at the end.
For a percentage, use division by 100: 15% of 80 is 80 * 15 / 100. The % key is a remainder operator. Expressions are processed in your browser and are not kept after you clear or reload the page.