There are 2 options to declare the interest, especially when it spans multiple financial years.
- At the time of maturity of the Fixed Deposit or (technically called as Cash method of accounting)
- Every year, on the basis of accrual i.e., interest earned but not yet received (techincally called as mercantile (accrual) basis of accounting)
If TDS is deducted on Fixed Deposit then as TDS will appear in Form 26AS you MUST to show it in the same year as Income Tax Department will be using the TDS in verifying your income tax return. Our article Viewing Form 26AS on TRACES explains it in detail.
If TDS is not deducted then you have a leeway and you can show it at maturity. The disadvantage of showing at maturity is that a higher amount would be deducted at the end.
If you have a Fixed Deposit or Recurring deposit spanning multiple financial years, say you invested in Jul 2010 for 3 or 5 years and no TDS has been deducted and you have not shown interest in Income Tax return till now, then wait till maturity to show it in Income Tax Return and then pay the tax. Yes you will have to pay a bigger chunk at the end but it would avoid the confusion.