About

Who publishes capitalgainstaxcalc.com, what qualifications stand behind it, and why the methodology is published in full.

Who runs this site

Capital Gains Tax Calculator is built and maintained by Kordal Systems. See our other free tools at Kordal Labs. We are based in Kolkata, India.

Not a licensed tax professional. We hold no tax credential: we are not CPAs, enrolled agents or attorneys. Nothing on this site is tax advice or a professional opinion, and no client relationship is created by using it. What stands behind the figures is not a credential — it is the published methodology: every number traced to a primary source, every omission listed, and the whole derivation shown on screen.

Why this site exists

Most capital gains calculators show you one number and no reasoning. Several of the best-ranked ones also make two specific errors: they label total income tax as “capital gains tax”, and they state an effective rate against your total income rather than against the gain — which makes the tax on a sale look far smaller than it is.

This calculator does neither. It separates the tax you would owe anyway from the tax the sale actually added, states the effective rate against the gain, and shows every step of the derivation with the rule and the citation behind it.

How the figures are maintained

Federal figures are transcribed from the IRS Revenue Procedure each October, when it is published, and are live before filing season.
State figures are refreshed from November through February as each revenue department publishes. Rate structures are read from the state tax code; a state whose figures cannot be verified is shown as not yet available rather than guessed at.
Every tax year gets its own dated file. Prior years are never edited, so an answer for 2026 remains reproducible after 2027 lands — which matters, because taxpayers amend returns for three years.
More than 500 automated tests run on every change, including seven scenarios cross-checked against an independent calculator and a check that recomputes each tax bracket from the Revenue Procedure's own printed figures.

What this site is not

It is an educational estimator. It is not tax advice, it cannot see your full return, and it does not model a substantial list of provisions —all of which are named explicitly rather than left for you to discover. Consult a CPA or enrolled agent before acting on any figure here.

Corrections and contact

If a figure is wrong, tell us with a source and it will be fixed. Tax corrections are treated as urgent.