Last updated: July 2026
Formula-Driven, Not a Black Box
Every calculator on this site applies a plain, published formula to the numbers you enter — for example, HRA exemption is the least of three amounts defined in Section 10(13A)-type rules, and EMI uses the standard reducing-balance loan formula. We do not use hidden weighting, estimation models, or AI-generated guesses to produce a result. Where a calculator's page includes a "How this is calculated" section, it shows the formula and, where useful, a worked example.
Browser-Only Processing
Most calculators run entirely as JavaScript in your browser. The numbers you type are used to compute a result on your device and are not sent to a server to produce that result. A small number of site features that are not calculators — such as the contact form — do transmit information, and that is covered separately in our Privacy Policy.
One Source of Truth for Rates
Every law-dependent figure a calculator needs — GST slabs, income-tax slabs, HRA city percentages, TDS thresholds, small-savings interest rates, EPF rates, and similar — is meant to live once in our central rate registry, alongside its effective date and, where confirmed, a link to the official source. Calculators read from this registry instead of having the same number typed into many pages, so a single correction updates every calculator that depends on it.
How Rates Are Kept Current
We update the registry when a Budget, a GST Council meeting, or a CBDT/CBIC notification changes a figure the site uses. Each entry records when the change takes effect and, where we can confirm it, the official source. See our Tax and Calculator Updates page for a running log of what changed and when.
What "Last Verified" Means
Where a calculator or the registry shows a "last verified" date, it means: on that date, the figure was checked against the source cited (or, where a live source could not be re-confirmed, against the most recent credible reporting of the notification). It is not a claim that the figure has been re-checked every single day since — tax rules can change between our verification passes, which is exactly why we ask you to confirm anything with financial consequences against the official source before you rely on it.
Known Simplifications
Some calculators make a stated simplifying assumption to keep the tool usable — for example, recurring deposit (RD) interest is estimated with monthly compounding on this site, while many banks compound quarterly; results will be close but not always identical to your bank's statement. Where a calculator makes an assumption like this, we try to say so directly on that page rather than presenting an approximation as exact.
What We Don’t Do
We don’t claim any result is legally certified, audited, or guaranteed correct. We don’t invent a citation, section number, or notification date we can’t confirm — where we’re unsure of the exact provision, we say so rather than making one up. And we don’t apply a newer rule to an older tax year silently; where a rule changed between years (like the HRA city list), the calculator lets you pick the year and shows the rule that actually applied then.
Questions About a Specific Calculation
If a result looks off, or you want to know exactly which source a figure came from, use the "Report an error" link near the calculator or email contact@toolsmasterhub.store. See our Editorial Policy for how we handle reports.