New Delhi, Aug. 28 -- Are you a retiree looking for a regular income without touching your principal? Fixed deposits (FDs) can provide a predictable stream of interest income, making them a popular option for retirees and individuals planning for retirement. But how much needs to be invested in an FD, and at what interest rate, to generate Rs.50,000 every month?

The answer depends largely on the FD interest rate and the investor's tax liability.

A monthly income of Rs.50,000 translates to Rs.6 lakh a year. If the entire interest earned is withdrawn as income and the principal remains intact, the required FD corpus can be estimated using a simple formula:

Note: Corpus estimates are indicative and assume interest-only withdrawals; actual...