New Delhi, April 3 -- Retirement calculators are too complex for most people to understand, and this complexity hides the inbuilt optimistic and incorrect assumptions that they make. As a result, people are saving too little for retirement, retiring earlier than their finances allow them to, and overspending during the early years of their retirement. Those looking for a clearer picture should, instead, use one simple formula to figure out how large a corpus they really need for retirement. How much money do you need to retire? The simple formula assumes that inflation is equal to investment returns, net of capital gains tax. Hence, the two cancel out, and you can ignore both these aspects. This makes the formula very simple. We will get to...