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CalculatorScientific Calculator
Type an expression directly or build it with the keys — the calculator shows exactly what it is about to evaluate before it evaluates it, which is the single biggest reason calculator answers surprise people.
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Precedence, and the implicit-multiplication trap
Operators are not evaluated left to right — powers happen before multiplication and division, which happen before addition and subtraction, and parentheses override all of it. 2+3×4 is 14, not 20, because the multiplication runs first. This calculator follows that standard order, and shows the typed expression above the result so you can check it read what you meant.
The subtler trap is implicit multiplication — writing 2(3+4) or 3sin(30) without a × sign. Both are accepted here and treated as multiplication, which matches how the expression reads on paper, but it is worth knowing that not every calculator agrees on how tightly implicit multiplication binds. Some systems treat 1/2(3) as 1/(2×3), others as (1/2)×3 — a genuinely disputed convention, not a bug in either. This calculator uses the second reading: implicit multiplication has the same precedence as an explicit ×, evaluated left to right alongside division.
Degrees vs radians is the most common wrong answer
sin(30) is 0.5 in degrees and about −0.988 in radians — both are "correct," they are just answering different questions, because 30 radians is a much larger angle (nearly 5 full turns) than 30 degrees. Every scientific calculator has to know which one you mean, and every wrong-looking trig result that is not a typo is almost always this setting. The angle mode above defaults to degrees; switch it before working in radians, and switch it back afterwards — leaving it on the wrong setting is the single most common source of "this calculator is broken" reports for any scientific calculator, not just this one.
| Input | As degrees | As radians |
|---|---|---|
| sin(30) | 0.5 | −0.98803 |
| cos(180) | −1 | −0.59846 |
| tan(45) | 1 | 1.61978 |
Why 0.1 + 0.2 does not show 0.3
Try it above: the result is 0.30000000000000004, not 0.3. This is not a bug in this calculator — it happens in essentially every programming language and most calculators, because computers store decimal fractions in binary floating point, and 0.1 and 0.2 cannot be represented exactly in binary any more than 1⁄3 can be written exactly in decimal. The stored values are tiny approximations of 0.1 and 0.2, and adding two approximations surfaces the rounding error. It only becomes visible because the display shows full precision rather than rounding it away, which is deliberate here — hiding it would be hiding a real limit of how the calculation works.
Questions people ask
What does the memory M+ button actually store?
The current result on screen. MR inserts that stored value into the expression wherever your cursor is, and MC resets it to zero. Memory is kept only for this browser tab and is lost on reload, since nothing here is saved to your device.
What does log mean versus ln?
log is base-10 logarithm here, and ln is the natural logarithm, base e. Some calculators default log to a different base, so check which convention a result needs to match before comparing it against another tool.
Can I use the keyboard instead of the buttons?
Yes — the expression field accepts typed input directly, including digits, the standard operators, parentheses, and function names like sin( or sqrt(. The buttons exist for symbols that are awkward to type, like π.
Why does the square root of a negative number show an error?
Because the result is not a real number — it would require an imaginary number, which this calculator does not support. The error is deliberate rather than a silently wrong answer.