Personal residual income, often called discretionary income, is the amount of income or salary left over after debt payments, like car loans and mortgages, have been paid each month. For example, Jim’s take-home pay is $3,000 a month. His mortgage payment, home equity loan, and car loan are the following respective: $1,000, $250, and $200. Using a residual income calculator, Jim would calculate his RI to be $1,550 a month. This is the amount of money he has left over after his monthly debt payments are make that he can put into savings or use to purchase new assets.
It’s easy to think as passive income as money earned while sitting on a beach sipping mojitos, but there is lots of work involved, says financial coach and retired hedge fund manager Todd Tresidder. If you’re worried about being able to save enough of your earnings to meet your retirement goals, building wealth through passive income is a strategy that might appeal to you.
You are also free to choose a fund that is based on any index that you want. For example, there are index funds set up for just about every market sector there is — energy, precious metals, banking, emerging markets — you name it. All you have to do is decide that you want to participate, then contribute money and sit back and relax. Your stock portfolio will then be on automatic pilot.
Real estate is the obvious choice if you are going to make money on your money. I personally am not at the point where I can do any of this in a meaningful way BUT my parents are and they now own a couple homes outright and are collecting income from them to power their retirement income. It makes a lot more sense for anyone that has a chunk of cash sitting in the bank and are planning on slowly drawing from it because you technically still have all that money in a property (or multiple properties) and can sell them if you really need the lump sum of cash but you’ll earn great interest payments until you do that.

In equity valuation, residual income represents an economic earnings stream and valuation method for estimating the intrinsic value of a company's common stock. The residual income valuation model values a company as the sum of book value and the present value of expected future residual income. Residual income attempts to measure economic profit, which is the profit remaining after the deduction of opportunity costs for all sources of capital.