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.

Berkshire Hathaway Inc.: An Owner's Manual (1999) - Letters to Shareholders (1957 - 2012)