# Case Conversion
**URL:** https://community.mp3tag.de/t/case-conversion/6047
**Category:** Support
**Created:** [January 10, 2008, 6:48am UTC](https://community.mp3tag.de/t/case-conversion/6047 "2008-01-10T06:48:39Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@Hubird](https://community.mp3tag.de/u/Hubird)
#### Post date: [January 10, 2008, 6:48am UTC](https://community.mp3tag.de/t/case-conversion/6047/1 "2008-01-10T06:48:39Z")
How do I make the case conversion not turn U.S.A. into U.s.a. ? I think it would be a good idea to build in some sort of rules for cases like this.
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [January 10, 2008, 7:40am UTC](https://community.mp3tag.de/t/case-conversion/6047/2 "2008-01-10T07:40:22Z")
Just enter the dot . at Words begin after.
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### Author:  [@Hubird](https://community.mp3tag.de/u/Hubird)
#### Post date: [January 10, 2008, 10:16am UTC](https://community.mp3tag.de/t/case-conversion/6047/3 "2008-01-10T10:16:47Z")
Thanks.
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### Author:  [@Hubird](https://community.mp3tag.de/u/Hubird)
#### Post date: [January 14, 2008, 10:30am UTC](https://community.mp3tag.de/t/case-conversion/6047/4 "2008-01-14T10:30:58Z")
> [@Hubird](#):
>
> Thanks.
It now seems to be changing the case on the file extension eg: .mp3 becomes .Mp3, can I stop this behavior. I would have thought that the file extensions would / should be left untouched.
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### Author:  [@Florian](https://community.mp3tag.de/u/Florian)
#### Post date: [January 15, 2008, 9:09pm UTC](https://community.mp3tag.de/t/case-conversion/6047/5 "2008-01-15T21:09:11Z")
Why not apply the case conversion on the tag of the file and use the converter Tag - Filename to rename the file?
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### Author:  [@Hubird](https://community.mp3tag.de/u/Hubird)
#### Post date: [January 17, 2008, 1:03pm UTC](https://community.mp3tag.de/t/case-conversion/6047/6 "2008-01-17T13:03:51Z")
That works but doing it that way also involves two steps to make the file name uppercase, whereas if the file extension was excluded from such operations it could be done in one step by leaving the case setting on “\_All”. Also mp3tag is useful for more than just tags (renaming, replacing in file names etc..) if someone had a bunch of music files that they did not have or want tags in that they wanted to convert the case on they would have to put up with an extensions such as .Mp3 and .Flac.
Now for what I think is some weird behavior:
If you leave the Case Conversion field set at "\_All" perform a case conversion the first letter of the file extension is turned to upper case, now immediately after (with out changing any settings) do a tag to file name the file extension is turned back to lower case.
I would have thought a tag to filename conversion would not affect the file extension at all (the tag has nothing to do with the file extension).
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### Author:  [@system](https://community.mp3tag.de/u/system)
#### Post date: [February 9, 2026, 12:20pm UTC](https://community.mp3tag.de/t/case-conversion/6047/7 "2026-02-09T12:20:42Z")