Forward P/E

Forward P/E prices a stock against earnings that have not happened yet: current share price divided by consensus estimated EPS for the next twelve months or next fiscal year. A fast grower that looks expensive at 40x trailing earnings might show 25x forward, because the denominator already includes the growth everyone expects.

That is both the appeal and the trap. The estimate in the denominator is an average of analyst forecasts, and those forecasts are wrong as a rule — analysts systematically start too optimistic and walk numbers down as the year progresses, so forward multiples are usually flattered at the moment you look at them. A stock at "just 18x forward" is at 24x if estimates get cut 25%, which happens routinely in cyclical sectors and in every recession.

Compare forward to trailing for a quick gauge of expectations: a big gap between the two is a growth bet, and the stock will be repriced on whether the estimates hold, not on the multiple itself.