All Calculators

Editorial Process — How We Build and Check These Calculators

Every calculator on EMICalcs produces a number that someone may act on — how much loan they can carry, what tax they owe, what a delay in filing costs. This page sets out exactly how those numbers are produced and checked, so you can judge how much weight to give them.

Who writes this

Javeed Shaik builds and maintains the site. I build and maintain every calculator on EMICalcs. Each formula is implemented directly from the published statutory rule or standard financial formula, covered by an automated test suite that runs on every deploy, and the figures are checked against the primary source listed on each page. I am not a chartered accountant or a registered investment adviser, and nothing here is personal financial advice.

That last sentence matters. Nothing here is personal financial advice, and no page should be treated as a substitute for a chartered accountant or a registered investment adviser who knows your circumstances. Where a figure is load-bearing for a filing or a large financial decision, check it against the primary source linked on the page.

Where the formulas come from

Calculators on this site fall into two groups, and they are sourced differently:

  • Standard financial formulas — EMI, compound interest, SIP future value, CAGR, XIRR-style projections. These are settled mathematics. The implementation is written directly from the formula and verified against worked examples.
  • Statutory calculators — income tax, GST, TDS, gratuity, EPF, PPF, NPS and similar. These depend on rates and thresholds set by law or notification, and they change. Each of these pages carries a Sources section listing the primary source for every statutory figure it uses — the Act, the rule, or the government department that publishes the rate.

How the numbers are tested

Each calculator ships with its own set of test cases — a fixed input paired with the expected output, checked to a 0.5% tolerance. Those tests run automatically on every build, and the build fails if any of them fail. At the last deploy the suite ran 119 test cases across 40 calculators.

This catches arithmetic regressions reliably. It does not catch everything: a test only proves the code still does what it did when the test was written. It cannot tell you a tax threshold changed last April. That is what the review dates and sources below are for.

Review dates on each page

Every calculator page carries a date in its byline, and the wording is deliberate:

  • "Last reviewed" means the statutory figures on that page were checked against the primary sources listed at the bottom of it, on that date.
  • "Last updated" means the page content changed on that date, but its figures have not been through a source check since.

We do not let a review date advance automatically when the site is rebuilt. A date that moved on every deploy would tell you nothing about whether anyone had actually looked.

What we do about rates that change

Statutory rates and thresholds move — in Budget announcements, in CBDT and CBIC notifications, in EPFO and small-savings rate revisions. Two consequences follow, and both are deliberate design choices:

  • Rates are editable wherever possible. On calculators like GST interest, every rate is an input you can change rather than a constant baked into the code. If the notified figure moves before we update the page, you can still get a correct answer.
  • We hedge rather than assert. Where a current statutory position could not be confirmed against a primary source at the time of writing, the page says so instead of stating it flatly.

Corrections

We have published mistakes and we will publish more. The policy is simple: when a factual error is found, the page is corrected at once, and if the error was material the correction is noted rather than quietly overwritten.

If you find a number that looks wrong — especially if you are a professional who works with these rules daily — please tell us at [email protected]. Corrections from readers who file these returns for a living are the single most valuable feedback this site receives, and they are acted on quickly.

Independence

EMICalcs is supported by advertising. We do not take payment for placement, we do not accept sponsored calculators, and no lender, broker, fund house or insurer has any influence over the figures a calculator returns or the conclusions an article reaches. Where an article says a product is a poor deal, that is what the arithmetic showed.

What we deliberately do not do

  • We do not ask you to create an account, and calculators run entirely in your browser — the numbers you type are not sent to a server.
  • We do not recommend specific funds, lenders, insurers or securities.
  • We do not present projections as predictions. A SIP calculator showing 12% is arithmetic on an assumption you chose, not a forecast.

Questions about anything on this page? Write to [email protected].