How we make sure the numbers are right

This is money content, so the standard is straightforward: publish the formula, test it, date it, and keep advertising well away from the math.

The standard we hold to

Every formula gets published

Each calculator carries a "See the math" panel that shows the exact expression used with your numbers substituted into it. Where we cannot show the formula, the tool does not ship.

Tested against genuine disclosures

Formulas sit in one shared library with unit tests covering hand-verified examples, worked examples from bank disclosures, and edge cases: zero inputs, very large deposits, penalties that exceed earned interest, and month-end maturity dates.

We flag every approximation

Penalties are estimated from APY where a bank would use its nominal rate, and the after-tax tools apply flat marginal rates instead of modelling brackets. Every one of those assumptions is stated on the page it affects.

Rates are dated rather than evergreen

Every rate figure carries the date it was last checked against the institution's published rates or a dated market roundup, and the table samples nationally available offers rather than covering the whole market. We would sooner show a timestamp you can judge than imply a freshness we cannot guarantee.

Independent review

Every calculator and guide is written and reviewed by the site's named author, then checked against primary sources and the published test suite. No second reviewer is credited on this build: no named, credentialed deposits professional has reviewed the site yet, and until one does, no reviewer will be listed — we will not invent a persona to look the part. Once that review happens, the reviewer and the date will appear on each page.