| The calculator shows an unexpected answer | The typed expression, parentheses or operation order may differ from the intended formula. | Review expression characters, insert explicit parentheses, evaluate components separately and compare with a simple known example. |
| Sine or cosine gives the wrong value | The angle unit is set to RAD or GRAD when the source problem expects degrees, or vice versa. | Select the correct DEG, RAD or GRAD mode and run the expression again. |
| Division returns an error or non-finite result | The denominator is zero or approaches a value that cannot yield a finite output. | Inspect the divisor, confirm grouping and avoid division by zero. |
| Square root of a negative number fails | A negative real number has no real square root and the selected numerical workflow may not support complex numbers. | Check the sign and choose an appropriate complex-number method elsewhere if the problem requires one. |
| Logarithm cannot be evaluated | The input is zero or negative in a real-valued logarithm calculation. | Supply a valid positive argument or confirm the problem requires complex logarithms. |
| A factorial result is too large | Factorials grow very rapidly and can exceed ordinary floating-point numeric limits. | Use a smaller supported input or a specialised arbitrary-precision method for huge factorials. |
| 0.1 plus 0.2 shows rounding artifacts | Binary floating-point cannot represent many decimal fractions exactly. | Use the rounded presentation for everyday arithmetic or a suitable exact decimal/rational method when precision is critical. |
| The result changes after switching number format | The representation or rounding convention changed; the mathematical value should be interpreted consistently. | Compare equivalent decimal and fractional forms and account for approximation or notation limits. |
| Fraction entry is interpreted incorrectly | The expression may be parsed as sequential divisions instead of one intended rational expression. | Use parentheses around numerator and denominator or enter the values in dedicated Fraction mode. |
| A percentage increase seems wrong | The calculation used the new value rather than original value as denominator. | Use (new-old)/old×100 and verify the original value is nonzero. |
| Discount and reverse discount give different bases | A discount is applied to a starting price, but reversing the discount requires dividing by the remaining percentage. | For a 20% discount divide the reduced price by 0.8 to find the starting price. |
| Compound interest differs from a bank illustration | Compounding period, interest convention, taxes, fees or rounding may differ. | Match periods and rates, then compare the bank's contractual method and disclosures. |
| Margin is lower than the calculated markup | Gross margin divides profit by selling price while markup divides by cost. | Choose the intended denominator and label the result accurately. |
| Negative hex output looks unusual | Signedness, width and two's-complement representation affect negative binary values. | Review the bit-width convention and validate against the language or hardware specification. |
| Bitwise NOT gives a surprising answer | NOT flips bits under a width or signed-integer convention that may differ from an imagined short binary string. | Confirm integer width, representation and mask before interpreting the result. |
| Quadratic solver reports no real roots | The discriminant may be negative, or coefficients were entered with the wrong signs. | Recheck a, b and c, compute b²-4ac and distinguish real solutions from complex ones. |
| Quadratic solver acts like a linear equation | The x² coefficient a may be zero. | Confirm a is nonzero for quadratic mode or solve as a linear equation when a=0. |
| Graph appears empty | The visible axis range may exclude the curve or the function may be undefined in that interval. | Reset or zoom out, check the function text and examine its domain. |
| Graph seems to miss an intercept | The viewport, sampling or scale may hide the crossing. | Pan or zoom, then verify roots analytically in Equation mode. |
| Unit conversion output is unexpectedly large | The source unit, destination unit or measurement category may be incorrect. | Check labels, unit symbols and whether a squared or cubed measurement is involved. |
| A keyboard shortcut does nothing | Focus may be on a different browser control or a device captures the shortcut. | Click the calculator expression field and use the on-screen keypad or documented input syntax. |
| Memory recalls an old figure | Stored memory was not cleared at the start of the new task. | Use MC to clear memory and MS to store the intended replacement value. |
| My previous calculations disappeared | Browser site data was cleared, or the work was performed in a private session or on another device. | Check available exported backups and save important histories externally after future sessions. |
| PDF, TXT or CSV export is missing information | The active export might cover a particular result or history selection, or formatting may change. | Verify the selected content, regenerate the file and inspect it in a suitable reader before sharing. |
| Copied CSV opens with wrong columns | Spreadsheet locale, comma delimiters or character encoding may affect import. | Use the spreadsheet application's import settings and choose a compatible delimiter and encoding. |
| SVG graph export is cropped | The exported view reflects the current viewport or selected graph bounds. | Reset or adjust zoom and axes before exporting and inspect the SVG after saving. |
| Result is Infinity or NaN | The expression exceeds numerical range or contains an undefined mathematical operation. | Review argument domains and numeric magnitudes, simplify the expression or use a specialist higher-precision system. |
| A huge number loses trailing digits | Standard floating-point arithmetic has finite significant-digit precision. | Avoid using this numerical result as an exact large integer; use an arbitrary-precision tool when every digit matters. |
| The shared calculation link reveals private numbers | Sharing a link can expose expression or result information in its URL or recipient context. | Review the link contents and avoid sharing confidential values through unapproved channels. |
| Dark mode or large text looks different on my device | Theme, browser scaling and accessibility settings may interact. | Try the supported system/light/dark theme and adjust large-font or high-contrast settings. |