No doubt financial adviser may give you an accurate number; but, we must always have a simple mathematical mindset to calculate the amount needed before we can really think of retirement. The simple mathematical calculation is involved two simple questions - what is your yearly expenditure? and what is the number of year on retirement?
For example, if your yearly spending is 100,000 and retirement number is 25, your ideal retirement fund will be 2.5 million.
Then, think about the yearly rate of return where the fund can generate a passive income of 100,000 a year from the 2.5 million retirement fund. If the retirement fund is able to generate a net 4% yearly rate of return in order to get 100,000 a year, you will definitely have enough money to spend in your whole retirement years until your heart stops pumping! It is basically more than 25 years, it is a perpetual passive income if you can hit the 4% rule!
Go check your yearly expenditure now! You will know the answer, start saving and investing for the 4%!