Report a problem
Use the contact form at https://freecalculatorsonline.com/contact with the page URL, exact statement or output, reproducible inputs, proposed correction and a primary supporting source. Never send personal financial records or credentials.
Triage
Output-changing defects receive immediate review and may cause temporary removal. Material definition or source conflicts are reviewed before the next published formula version.
Change record
Material formula changes update the visible review date and structured dateModified value. Copy edits that do not alter meaning may be applied without a formula-version change.
What counts as a correction
An arithmetic error, a formula that does not match its stated description, a definition inconsistent with its cited source, a stale statutory figure, a broken or redirected source link, or an interpretation that overstates what the calculation supports. Design preferences and disagreements about which model is most appropriate are considered separately and are not corrections.
What to include in a report
The page URL, the exact inputs entered, the result shown, the result you expected, and the basis for expecting it: a formula, a source, or a worked calculation. Enough to reproduce the issue. Reports without inputs are frequently impossible to investigate, because a result cannot be checked without knowing what produced it.
How reports are handled
Every report is reproduced before anything is changed. If the figure is wrong, the calculation is fixed, the review date moves, and every dependent page is re-checked. If the figure is right, the reply explains why, because a report that turns out to be correct behaviour usually indicates the page failed to explain something.
What never to send
Do not include account numbers, government identifiers, credentials, or documents containing them. A correction can always be reproduced from the numeric inputs alone, and no correction requires personal financial records.
Corrections that change a result
Where a fix changes a published figure, the affected calculator's version increments and its review date moves. Where the error affected a formula shared by several calculators, every calculator using that formula is re-checked , not only the page that was reported.
What to include in a report
| Include | Why it is needed |
|---|---|
| The page URL | So the exact calculator and formula version can be found. |
| The exact inputs you entered | A result cannot be checked without knowing what produced it. |
| The result shown | So it can be reproduced. |
| The result you expected | So the difference can be measured. |
| The basis for expecting it | A formula, a source or a worked calculation that supports the expected figure. |
Frequently asked questions
How do I report a mistake in a calculator?
Use the contact form and send the page URL, the exact inputs you entered, the result shown, the result you expected and the basis for expecting it: a formula, a source or a worked calculation. With those details the issue can be reproduced without guessing.
What counts as a correction?
An arithmetic error, a formula that does not match its stated description, a definition inconsistent with its cited source, a stale statutory figure, a broken or redirected source link, or an interpretation that overstates what the calculation supports.
Is a disagreement about which model is best a correction?
No. Design preferences and disagreements about which model is most appropriate are considered separately and are not corrections.
What happens after I send a report?
Every report is reproduced before anything is changed. If the figure is wrong, the calculation is fixed, the review date moves and every calculator sharing that formula is re-checked, not only the page you reported.
What if the result turns out to be right?
The reply explains why. A report about correct behaviour usually means the page failed to explain something clearly enough.
What should I never send in a report?
Account numbers, government identifiers, credentials or documents containing them. A correction can always be reproduced from the numeric inputs alone. No correction needs personal financial records.
How quickly are wrong results handled?
Output-changing defects receive immediate review and may cause temporary removal of the calculator while they are investigated. Material definition or source conflicts are reviewed before the next published formula version.
How do I know a correction was made?
Where a fix changes a published figure, the calculator's version increments and its visible review date and structured dateModified value move. Copy edits that do not alter meaning may be applied without a formula-version change.