Two Questions, Not One
Most capital-gains calculators answer only "how much tax do I owe?" For a property sale that is half the story, because the law gives you two levers. First, if you bought before 23 July 2024, you may choose between paying 12.5% on the plain gain or 20% on the inflation-indexed gain. Second, you can reduce or wipe out the tax entirely by reinvesting — in another house under Section 54 or 54F, or in bonds under Section 54EC. This calculator does both, and it computes the reinvestment relief separately under each method, because they interact.
Which Exemption You Can Claim Depends on What You Sold
This is where people most often go wrong. If you sold a residential house and bought another, you claim Section 54, and the exemption is simply the lower of your capital gain and the new house's cost. If you sold a plot, land or commercial property and bought a house, you claim Section 54F — and that exemption is proportional: it equals your gain × (amount invested ÷ net sale consideration). Invest half the sale proceeds and only half your gain is exempt. Invest the whole net consideration and the whole gain is exempt. That proportionality catches many sellers out, because they assume investing an amount equal to the gain is enough — under 54F it is not.
Section 54EC Bonds
For land or a building, you can also put up to ₹50 lakh into bonds issued by REC, PFC or IRFC within six months of the sale. The limit is per financial year, the lock-in is five years, and the interest (currently around 5.25%) is fully taxable each year — only the capital gain is exempted, not the bond income. Section 54EC stacks with 54 or 54F, so a seller can combine a new house with bonds to cover a larger gain.
Why the Indexation Choice and the Exemption Interact
Indexation shrinks the gain — sometimes dramatically on a property held fifteen or twenty years. A reinvestment that leaves the plain gain partly taxable can wipe out the indexed gain completely. That means the cheaper method can flip once reinvestment is taken into account, which is why this calculator applies the exemptions under both methods before comparing. A tool that picks the method first and applies relief afterwards can point you at the wrong one.
The Deadlines That Actually Matter
For Section 54 and 54F, the new house must be bought within one year before or two years after the sale, or built within three years. For 54EC, the bonds must be bought within six months. If your return falls due before you have reinvested, deposit the money in a Capital Gains Account Scheme account with a bank before the filing deadline — that preserves the claim while you complete the purchase. Selling the new house within three years (or the bonds within five) reverses the exemption and the tax comes back.
Surcharge is excluded here because it depends on your total income. For gains on shares, mutual funds or gold, use the general capital gains calculator; to look up an index value on its own, see the indexation calculator.