Some numbers look simple and mislead. Each check below starts from an example, and you can change every input to see the arithmetic move.
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 (%) = (1 ÷ (1 − fall ÷ 100) − 1) × 100
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.
Real return = (1 + nominal) ÷ (1 + inflation) − 1
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%.
End value = Amount × (1 + (return − cost) ÷ 100)^years, compared with Amount × (1 + return ÷ 100)^years.
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.
Uses the EMI formula (see the EMI calculator) and compares total interest with the amount borrowed.
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.
Rule of 72: years ≈ 72 ÷ rate. Exact: years = ln 2 ÷ ln(1 + rate ÷ 100).
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.
