The amount needed to invest in an annuity plan can vary based on your requirements. To begin with, you need to calculate the amount you will need during your retirement. For this, you need to consider factors like your lifestyle expenses, medical costs, amount needed to fulfil your post-retirement goals like traveling, pursing a hobby, and more. You must also factor in inflation in this calculation. Once you know the amount you need during retirement, you can calculate the amount you need to invest in an annuity plan so that you can enjoy a financially independent retirement.