Before you open a fixed deposit (FD) in a bank, it is natural to compare the term deposit interest rate with that of others. Most banks offer 3 to 7 per cent per annum on their fixed deposits based on their maturity.

The main rule is this: the interest rate will increase as the term increases. So, if you want to maximize your returns, you should invest in a bank FD for the long term.

Have you ever wondered how long it takes to double your investment?

Typically, at an interest rate of 'x' = 72, it takes' x 'the number of years it takes to double the investment. That is, when the interest rate is 7% per annum, it takes 10.28 years to double the money. While the FD interest rate is 7.2 per cent per annum, it takes exactly 10 years to double the money.

The six banks that offer the highest interest rates are:

HDFC Bank: HDFC Bank offers an interest rate of 7% on fixed deposits for 10 years for ordinary citizens and 7.5% for senior citizens. If you continue to invest for 10 years, the amount invested will almost double. For example, if you deposit ₹100, it will grow to ₹196.72 in 10 years, and in the case of senior citizens, it will grow to ₹206, i.e., more than double.

ICICI Bank: This private bank offers an interest rate of 6.9 per cent on fixed deposits for 10 years and 7.4 per cent for senior citizens. This means that if someone invests Rs 100, it will grow to Rs 194.88 in 10 years and if that investor is a senior citizen, the investment will grow to Rs 204.

State Bank of India (SBI), the largest state-run lender, is offering 6.5 per cent to ordinary citizens and 7.5 per cent to senior citizens on fixed deposits for 10 years. This means that if one deposits Rs 100 in SBI FD, it will grow to Rs 187.71 in 10 years. In case of senior citizens, it will increase to Rs 206.

Kotak Mahindra Bank: This private bank offers 6.2 per cent to ordinary citizens and 6.7 per cent to senior citizens on fixed deposits for 10 years. This means that if someone invests ₹100 in a fixed deposit, it will grow to ₹182 in 10 years in the case of the common man and ₹191 for the senior citizen.

Bank of Baroda: This state-run bank offers 6.5 per cent on 10-year fixed deposits and 7.5 per cent for senior citizens. This indicates that if someone invests ₹100 in a fixed deposit, the amount will grow to ₹187.71 in 10 years and in the case of senior citizens, the amount will grow more than double i.e. to ₹206.

Punjab National Bank: The second-largest state lender offers an interest rate of 6.50 per cent on fixed deposits for 10 years for the general public and 7.30 per cent for senior citizens. This means that if someone deposits ₹100 in a fixed deposit in PNB, the amount will grow to ₹187.71 in 10 years and ₹202 in case of senior citizens.