FanGraphs Guts! (wOBA & FIP Constants)

One of the frequently asked questions we get is what are the wOBA constants for a particular season, or what is the FIP constant?

Now there is a single exportable page with all the answers: FanGraphs Guts!

– Any field with a “w” in front of it is a wOBA constant

– R/PA is runs per plate appearance

– R/W is the runs to wins conversion number

– cFIP is the FIP constant

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David Appelman is the creator of FanGraphs.

14 Responses to “FanGraphs Guts! (wOBA & FIP Constants)”

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  1. Bryz says:

    Awesome! The FIP constant has been something I’ve always wanted available.

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    • Ludwig von Koopa says:

      Well I guess I can stop randomly plugging in other constants to try and reverse-engineer the formula.

      Avogadro’s number got me a touch closer than Planck’s constant. Graham’s number was the least useful.

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  2. MikeS says:

    Fangraphs has guts and guts are enough!

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  3. Jack says:

    Could we also get a way to limit the data to a certain period of years (like 1902-2012 or 1993-2004). If its not to much work, it would be helpful.

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  4. Ben Hall says:

    Can you put in a link somewhere? Maybe from the library? If I’m not on my computer I’d like to be able to find it easily.

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  5. debater12 says:

    Is there a place on the site this will be kept outside of this post? How do we access this from the homepage?

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  6. chiefglockandhummer says:


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  7. FreeRedbird says:

    this is really awesome.

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  8. jrogers says:

    Is Reaching on Error included in wOBA?

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  9. studes says:

    So the FIP constant and other constants don’t vary between leagues within a given year?

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    • You can calculate them specifically by league. I’m not sure what they look like for wOBA, but I do know that it doesn’t really make much of a difference when you calculate FIP by league. When you use league ERA and league FIP the constants work out to be really similar.

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      • studes says:

        We might interpret “really similar” differently. ;)

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      • The average difference since 1950 has been .002 for AL and .003 for NL.

        With the maximum being about .15. In 1970 it was .2 and it’s never been more than .11 since 1980.

        Generally you want to add about .05 to AL pitchers and subtract .05 from NL pitchers if you do it by league, but that’s not always the case.

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