Intrinsic value can be defined simply: It is the discounted value of the cash that can be taken out of a business during its remaining life. The calculation of intrinsic value, though, is not so simple. As our definition suggests, intrinsic value is an estimate rather than a precise figure, and it is additionally an estimate that must be changed if interest rates move or forecasts of future cash flows are revised.
Warren Buffett (2009). “Warren Buffett on Business: Principles from the Sage of Omaha”, p.220, John Wiley & Sons