Calculator Matters is an independent project maintained by a single operator who is directly accountable for its accuracy. We work to keep every formula, example, and result correct, but we do not claim perfection — formulas can be implemented incorrectly, references can change, and edge cases can surface. Accuracy reports are treated seriously and confirmed errors are fixed as quickly as reasonably possible.
How to report an error
Email corrections@calculatormatters.com or use the contact page. Reporting an issue is always free and never requires an account.
What to include
To help us reproduce and fix an issue quickly, please include where you can:
- The calculator name or page URL.
- The exact inputs you entered.
- The result you saw, and the result you expected.
- A reference or source for the expected result, if you have one.
- Your device and browser, if the problem looks like a display or input bug.
How we review a report
We reproduce the issue using the inputs you supply, then check the calculator's formula and implementation against authoritative references and the worked example on the page. We classify each report as a formula error, an input or unit-handling error, a display or rounding issue, a content error in the surrounding explanation, or "working as intended" (often a difference in assumptions, which we may then state more clearly).
How we update a corrected page
- We fix the formula, input handling, example, or wording at the source.
- We re-check the worked example against the corrected formula before publishing.
- We update the page's "last updated" date when a correction changes a result, a formula, or a materially important explanation. Minor typo or styling fixes may not change the date.
- For a significant correction that changed a published result, we note what changed so returning users understand why a number may now differ.
Rate and rule changes
Some results depend on figures that change over time, such as tax brackets, contribution limits, or stamp-duty rates. For those tools we label the relevant year or note that rates are illustrative, and we link to the official source for the current figure. If you let us know a published rate is out of date, we will review and update it.
Our accuracy commitment — and its limits
We aim for every calculator to be correct and clearly explained, and we act on confirmed errors promptly. We do not, however, guarantee that every result is free of error or current at all times, and results remain educational estimates rather than professional advice. For decisions that matter, verify the inputs and consult a qualified professional. See our full Disclaimer and our Methodology for how we build and check tools.