How to Calculate Your RERA Delayed-Possession Interest

If your builder missed the possession date written in your Agreement for Sale, Section 18 of the Real Estate (Regulation and Development) Act, 2016 entitles you to interest on every rupee you have paid — from the day the builder defaulted until the day you receive possession or a full refund. The calculator above automates this arithmetic so you don't need a spreadsheet or a CA.

Step 1 — Choose your state

Start by selecting the state where the project is registered. Each state RERA authority sets its own interest formula. For example, MahaRERA and HRERA apply simple interest at SBI MCLR + 2%, while UP RERA uses simple interest at SBI MCLR + 1% and K-RERA uses simple interest at SBI MCLR + 2%. Picking the right state loads the correct formula automatically.

Step 2 — Enter the key dates

You need two dates from your sale agreement: the committed possession date (the deadline your builder promised) and the actual or expected possession date (when you received or expect to receive the property). The gap between these two dates is the delay period on which interest accrues.

Step 3 — Add your payment schedule

Click "Add Payment" for each instalment you made — enter the date you paid and the amount. Interest is computed separately on each tranche from its payment date, not just on the lump sum. This per-instalment approach matches how RERA tribunals actually adjudicate claims, and it often results in a higher total than a flat calculation.

If you paid in a single lump sum, add just one entry. If you made construction-linked payments across several milestones, add each one individually with its exact date and amount.

Step 4 — Review the results

After you click "Calculate," the tool generates a detailed, line-by-line breakdown showing:

• The delay period for each instalment (in days and months).
• The interest rate applied and whether it is simple or compounded monthly.
• The interest amount accrued on each instalment.
• A grand total of principal paid plus total interest owed.

You can print or save this breakdown as a PDF — it serves as supporting documentation if you file a complaint with your state RERA authority or an adjudicating officer.

How the interest formula works

Under Section 18, interest is prescribed at SBI's Marginal Cost of Lending Rate plus two percentage points. Most state presets in this calculator use SBI's highest MCLR (3-year tenor, currently 8.80%) + 2.00% = 10.80% p.a., while a few states use the 1-year MCLR (8.70%) + 2.00% = 10.70% p.a. All state presets apply simple interest as the standard method, calculated as Principal × Rate × Days ÷ 365.

The calculator uses the rate and method tied to each state preset, but you can override both the rate and compounding type in "Custom" mode if your tribunal order specifies different terms.

When to consult a lawyer

This calculator gives you a reliable estimate, not legal advice. Consider speaking with a RERA-practising advocate if:

• Your builder disputes the committed possession date or claims a force-majeure extension.
• You want to claim additional compensation beyond statutory interest (mental agony, rental losses).
• The delay exceeds several years and you are weighing a refund with interest versus waiting for possession.
• Your agreement includes arbitration clauses that may affect RERA jurisdiction.

Having your calculated interest figure ready before a consultation saves time and gives your lawyer concrete numbers to work with from the outset.

Learn more about your RERA rights

If you want to understand the full legal framework behind RERA compensation for delay — including your rights under Section 18, the difference between RERA compensation and RERA penalty, how much compensation you can claim, state-wise differences, and key Supreme Court rulings — read our complete guide to RERA compensation for delay in possession. It covers everything you need to know before filing a complaint or consulting a lawyer.