# MAC - Export - length does not work but \_length does

**URL:** https://community.mp3tag.de/t/mac-export-length-does-not-work-but-length-does/69585
**Category:** Mac
**Created:** [August 31, 2025, 2:32am UTC](https://community.mp3tag.de/t/mac-export-length-does-not-work-but-length-does/69585 "2025-08-31T02:32:10Z")
**Posts on this page:** 1
**Showing post:** 2

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### Author: ![ohrenkino](https://community.mp3tag.de/user_avatar/community.mp3tag.de/ohrenkino/32/4843_2.png) [@ohrenkino](https://community.mp3tag.de/u/ohrenkino)
#### Post date: [August 31, 2025, 6:28am UTC](https://community.mp3tag.de/t/mac-export-length-does-not-work-but-length-does/69585/2 "2025-08-31T06:28:39Z")

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The information about the length written by the ripper is a read-only property for MP3tag and can only be accessed with \_LENGTH.  
The field LENGTH which is part of the ID3 standard can contain anything.  
To get something in square brackets, write them as `'['%_length%']'`.  
See also the documentation about special characters:

> [@Format Strings and Available Placeholders](https://community.mp3tag.de/t/format-strings-and-available-placeholders/51688):
>
> Mp3tag uses format strings in various of its features to describe the structure of file names and imported data. A format string is built of either standard text (e.g., Music), placeholders (such as %artist%, %title%, ...), or slash characters / that usually denote directory structures. Characters with Special Functionality Some characters have special functionality and need to be treated with extra care. If you experience some unexpected behavior when using format string, check if some of t…

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