# EPUBCheck RSC-027: XML document is encoded in UTF-16. It…

Source: https://epublab.com/epubcheck/rsc-027/ (updated 2026-11-03)

EPUBCheck RSC-027 is a warning message: “XML document is encoded in UTF-16. It should be encoded in UTF-8 instead.” An XML file is encoded in UTF-16; EPUB recommends UTF-8 for every XML document.

- Official message (EPUBCheck 5.4.0): XML document is encoded in UTF-16. It should be encoded in UTF-8 instead.
- Default severity: Warning

## Typical causes

- A file saved in UTF-16 by an editor, common with some Windows tools.

## How to fix it

- Re-save the file as UTF-8 and make its XML declaration say encoding="UTF-8".

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EPUBLab.