We Have Reset the Starting Numbers on Every Calculator

Every calculator on this site now opens on the same property: an ₹80 lakh metro flat, with the same society maintenance, the same property tax, the same insurance, and the same view of what your money would earn if you invested it instead. Until today they disagreed with each other, and on the main calculator the starting numbers were quietly leaning towards one answer.

They were describing different flats

Open the Rent vs Buy calculator and that flat carried ₹42,000 of society maintenance a year. Open the Property Investment calculator and the same flat carried ₹30,000. Insurance was ₹3,500 on one and ₹10,000 on the other. Stamp duty and registration came to 7% of the price on one and 6.25% on the other. Two calculators, one flat, two different properties.

None of that was deliberate. Figures get set at different times, and nothing forces them to agree. The rebuild in July corrected the calculations themselves; this pass corrects the numbers they open with. They agree now, and a test holds them together so they cannot drift apart again. One number still differs on purpose: lenders price a let-out property above an owner-occupied one, so the Property Investment calculator borrows at 8.75% where the rest use 8.25%.

The starting numbers were taking a side

The larger problem turned up only when we asked a different question of the Rent vs Buy calculator. For each pre-filled figure, how far would it have to move before the verdict changed hands?

Property appreciation was set at 5.00%, and the answer turned over at 4.95%. Rent escalation was 10%, and it turned at 9.89%. Monthly rent was ₹25,000, and it turned at ₹24,821. The expected investment return was 9%, and it turned at 9.06%.

Four separate figures, each sitting within a whisker of its own tipping point, and every one of them on the side that favoured buying. That is not a balanced starting point. It is a coin standing on its edge, where the smallest nudge decides everything.

Each of those numbers also sat at the end of its own plausible range that helped buying: rent escalation at the top of the 5–10% that Indian leases actually use, rent at the top of the 2–4% gross yield our own research puts on Indian metros, and the expected return below the 10–12% equity index funds have returned over long periods. Taken one at a time, each was arguable. Taken together, they leaned.

The rule we follow now

Every uncertain figure is the middle of a range we can point at, picked one number at a time, and never adjusted because of the answer it produces.

That last part matters more than it sounds. Nudging the starting numbers until the result looks even-handed would be its own thumb on the scale, just a quieter one. So we do not do it. Each figure is chosen on its own merits and the verdict falls where it falls. On the numbers as they now stand, renting and investing comes out ahead over fifteen years. Raise the appreciation rate to about 7.5% and buying wins instead. Both live in the calculator; neither lives in the defaults.

If you have used these before

Your results will differ from what you saw last week, and the new figures are the more defensible ones. Every one of them is still yours to change. They are a starting point for a typical metro flat, not a claim about your city, your building, or your loan.

The Rent vs Buy and Property Investment calculators now also show how much room the answer has: what appreciation, rent, or return would have to be before the verdict changes hands. If your answer turns on a tenth of a percent, that is worth knowing before you act on it.

The other calculators get the same treatment next.