Stat FIP

FIP (Fielding Independent ERA) is basically an ERA (earned run average) equivalent for pitchers that strips out all the vicissitudes of fielding. The idea is to isolate events for which the pitcher alone is responsible and thus produce a "truer" picture of how a pitcher is performing.

The formula is as follows:

13 * HR + 3 * BB+HBP - 2*K /IP + FIP constant

The constant is variable to the league and is derived by this formula:

FIP constant = league ERA - ((13 * league HR) + (3 * ( league BB + league HBP)) - (2 * league K)) / league IP

See https://legacy.baseballprospectus.com/glossary/index.php?search=FIP for more information.