How we verify
A calculator you can't check is a black box. Every tool on TrueSums ships against the same standard:
1. The formula is cited
Each tool page names the method it uses and links the source it came from — a government publication, a standards body, or a peer-reviewed reference. If we can't source the math, we don't build the tool.
2. Five published test cases must pass
Before a tool goes live, it must reproduce five worked examples taken from authoritative sources — not examples we invented ourselves. These test cases run automatically on every code change, so an update can't silently break the math.
3. Changing data is dated
Tax rates, contribution limits, and guidelines change. Any tool that depends on them shows a "data last verified" date, and tools with stale data are flagged for review.
4. Corrections are welcome
If a number here is wrong, we want to know. Tell us and we'll re-check the tool against its sources and publish the fix.
Our tools are for estimation and planning. They are not a substitute for professional financial, tax, medical, or legal advice.