How do I convert an ANSI encoded file to UTF-8 with Notepad++?

Regarding this part:

When I convert it to UTF-8 without bom and close file, the file is again ANSI when I reopen.

The easiest solution is to avoid the problem entirely by properly configuring Notepad++.

Try Settings -> Preferences -> New document -> Encoding -> choose UTF-8 without BOM, and check Apply to opened ANSI files.

That way all the opened ANSI files will be treated as UTF-8 without BOM.

For explanation what's going on, read the comments below this answer.

To fully learn about Unicode and UTF-8, read this excellent article from Joel Spolsky.

If you don't have non-ASCII characters (codepoints 128 and above) in your file, UTF-8 without BOM is the same as ASCII, byte for byte - so Notepad++ will guess wrong.

What you need to do is to specify the character encoding when serving the AJAX response - e.g. with PHP, you'd do this:

header('Content-Type: application/json; charset=utf-8');

The important part is to specify the charset with every JS response - else IE will fall back to user's system default encoding, which is wrong most of the time.

Maybe this is not the answer you needed, but I encountered similar problem, so I decided to put it here.

I needed to convert 500 xml files to UTF8 via Notepad++. Why Notepad++? When I used the option "Encode in UTF8" (many other converters use the same logic) it messed up all special characters, so I had to use "Convert to UTF8" explicitly.

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Here some simple steps to convert multiple files via Notepad++ without messing up with special characters (for ex. diacritical marks).

1. Run Notepad++ and then open menu Plugins->Plugin Manager->Show Plugin Manager
2. Install Python Script. When plugin is installed, restart the application.
3. Choose menu Plugins->Python Script->New script.
4. Choose its name, and then past the following code:

convertToUTF8.py

import os
import sys
from Npp import notepad # import it first!

filePathSrc="C:\\Users\\" # Path to the folder with files to convert
for root, dirs, files in os.walk(filePathSrc):
    for fn in files: 
        if fn[-4:] == '.xml': # Specify type of the files
            notepad.open(root + "\\" + fn)      
            notepad.runMenuCommand("Encoding", "Convert to UTF-8")
            # notepad.save()
            # if you try to save/replace the file, an annoying confirmation window would popup.
            notepad.saveAs("{}{}".format(fn[:-4], '_utf8.xml')) 
            notepad.close()

After all, run the script