Methodology — How DesiCalc Verifies Tax Rates

This page explains where the numbers inside every DesiCalc calculator come from, how they are checked before publication, and what we do when a rate changes. It is a description of our internal process, not tax or legal advice.

What we cover

DesiCalc publishes calculators for the taxes and fees that ordinary Indian households and small businesses meet most often:

Income Tax for FY 2026-27, across the old and new regimes, including rebate and surcharge steps. Rates are anchored to the Income Tax Department at incometax.gov.in.
Stamp Duty for 28 states plus Delhi, including gender and joint-ownership concessions where the state provides them.
RTO Road Tax for 28 states plus Delhi, covering private cars, two-wheelers, and commercial seating brackets. Vehicle and registration rules are tracked through the Ministry of Road Transport and Highways at morth.nic.in and the Parivahan portal at parivahan.gov.in.
HRA exemption under the Income Tax Act, and GST splits tracked through the Central Board of Indirect Taxes and Customs at cbic.gov.in.

Source hierarchy

When two sources disagree, the one higher in this list wins:

A central or state gazette notification. This is the legal instrument that actually sets a rate.
The official website of the department that administers the tax or fee.
An official notification PDF published by that department.
Secondary financial publications, used only to cross-check a reading and never as the sole basis for a rate.

If we cannot reach a primary source for a figure, we leave that figure out rather than publishing a secondary-only number.

How rates are verified

Every stored rate is checked against its primary source, then compared with the value already in our data files. A value is changed only when the primary source itself changed. We do not adjust a rate because a secondary article reports a different number. Verification dates are recorded in the page changelog below and in the page's dateModified value; the current review date for the full dataset is 2026-10-30. Where a state levies additional charges such as registration fees, metro cess, or surcharges, each component is sourced separately rather than bundled into one unverified total.

When we update

After the Union Budget, when income tax slabs, rebates, or surcharge thresholds are announced.
After a state government issues a stamp duty or transport notification.
On a monthly audit of all 58 state pages, whether or not a notification has been published.

Corrections

If a rate looks wrong, email desicalc@gmail.com with the calculator, the state, and the official source you are comparing against. Errors we can verify are fixed within 48 hours and recorded in the changelog below so the change is visible.

Limitations

The calculators are estimates. The registration authority's final demand is authoritative, and circle rates vary by locality within a state, so a district-level rate may differ from the state-level figure we use. Income tax outcomes also depend on deductions and exemptions that a calculator cannot see. Treat every result as a planning aid and confirm the final amount with the relevant department or a qualified professional.

Changelog

2026-10-30 — Full re-verification of RTO and stamp duty rates; trust pages published.