Asset has two classes, one is called financial asset and the other called non-financial asset. Financial asset includes stock, bond and cash which are very liquid. Non-financial asset includes real estate, land, antique, arts and jewelries which are not easy to buy or sell in a moment of notice. Adding all these assets together, you will have your total assets.
Total Assets = Financial Assets + Non-financial Assets
To calculate your net asset, you need to subtract your debts from your total assets.
Net Assets = Total Assets – Debts
People usually confuse about assets that don't generate incomes, and there are even some people who don't think that these are assets, like primary residence and cars. Basically, anything you own which have values are assets.
For retirement planning, we usually only consider the assets that can generate incomes, like investment funds, bonds, rental properties, etc.