Reality corner

Some numbers look simple and mislead. Each check below starts from an example, and you can change every input to see the arithmetic move.

India real estate tracker

What the official house price index recorded, city by city.

A map and a table of year-on-year change in the NHB Residex house price index, with the quarter and source beside every number.

Open the tracker

The recovery trap

A 50% fall needs a 100% rise to get back to even.

Percentages apply to different bases. After a fall, the base is smaller, so the same percentage rise recovers less than was lost.

Rise needed to get back to even
100.00%
Value left after the fall, per ₹100
₹50
Formula and assumptions

Rise needed (%) = (1 ÷ (1 − fall ÷ 100) − 1) × 100

  • Pure arithmetic on percentages. It says nothing about whether any price will rise or fall.

The real return

A 7% return with 5% inflation is about 1.9% in buying power.

What matters for what you can buy is the return after inflation. The gap between the two rates is not simply subtracted; it is divided.

An example figure you can change

Real return (buying power)
1.90%
Simple difference of the two rates
2.00%
Formula and assumptions

Real return = (1 + nominal) ÷ (1 + inflation) − 1

  • Both rates are example inputs. Taxes and costs are not included.

The cost you do not see

A 1% yearly cost does not take 1% of the end value. It takes far more.

The cost comes out every year, so the money it removes stops compounding too. Over 20 years the gap is a much larger share than 1%.

An example figure

End value with no cost
₹33,63,750
End value after the yearly cost
₹28,02,205
Difference
₹5,61,545
Difference as a share of the no-cost value
16.69%
Formula and assumptions

End value = Amount × (1 + (return − cost) ÷ 100)^years, compared with Amount × (1 + return ÷ 100)^years.

  • Simplified: the cost is subtracted from the yearly rate. Real products charge in different ways.
  • Example inputs only. This does not compare or rate any product.

The true price of a loan

On a 25-year loan at 9%, the interest is more than the amount borrowed.

In the early years most of each instalment is interest, because the balance is still large. That is why tenure matters as much as the rate.

Total interest paid
₹75,87,945
Interest as a share of the amount borrowed
151.76%
Share of the first year’s payments that is interest
88.92%
Formula and assumptions

Uses the EMI formula (see the EMI calculator) and compares total interest with the amount borrowed.

  • Fixed rate, reducing balance, no fees or prepayments. Example inputs.

The rule of 72

Divide 72 by the yearly rate to estimate the years to double.

At 8% a year a value doubles in about 9 years. The rule is an approximation; the exact figure is shown alongside.

Years to double (rule of 72)
9 years
Years to double (exact)
9 years
Formula and assumptions

Rule of 72: years ≈ 72 ÷ rate. Exact: years = ln 2 ÷ ln(1 + rate ÷ 100).

  • Constant yearly growth. The rule works best for rates between about 6% and 10%.

The examples use round numbers so the point is easy to see. They are not forecasts and they say nothing about any company, fund or product. For more, try the inflation calculator and the EMI calculator.

These tools do arithmetic on the numbers you enter. They are for illustration and education. They do not predict returns, and they are not investment, tax or financial advice. Returns are not guaranteed.