PO to MO Converter

A .po file is the human-editable half of a GNU gettext translation — plain text, one msgid/msgstr pair per string. Nothing that actually loads translations at runtime reads it directly, though: PHP, Python, glibc, and WordPress all expect the compiled binary .mo (Machine Object) format instead, normally produced by the command-line msgfmt tool. This converter does the same compile step in your browser, so you can go from .po to .mo without installing gettext or a PHP/Python toolchain.

How to use it

Paste your .po file's contents into the text box, or upload the file directly — either way, the file never leaves your browser. Click Compile to MO and download the resulting messages.mo.

What it supports

• Multi-line strings — a msgid/msgstr split across several quoted lines is joined back together, same as msgfmt.
• Plural forms — msgid_plural and indexed msgstr[0], msgstr[1], … are compiled into gettext's NUL-joined binary plural encoding, so ngettext()/_n() lookups work correctly.
• Message contexts — a msgctxt is folded into the compiled key exactly as pgettext()/_x() expect.
• Fuzzy and untranslated entries are skipped, matching msgfmt's default behavior (no --use-fuzzy). A string flagged #, fuzzy is a rough machine guess a translator hasn't confirmed — shipping it as a real translation would be worse than falling back to the original text, so it's left out of the compiled catalog rather than trusted.
• Obsolete entries (#~-prefixed, left behind by msgmerge when a string disappears from the source) are dropped, same as a real compile.

Privacy

Everything happens client-side — parsing the .po text and assembling the binary .mo file both run in your browser. Nothing is uploaded to a server.

Why isn't my translated string showing up in the .mo file?

Check whether it's flagged #, fuzzy in the .po file. Fuzzy strings are intentionally left out of the compiled catalog (see above) — remove the fuzzy flag once you've confirmed the translation is correct, then recompile.

Does the compiled file work with WordPress?

Yes — WordPress (and any other PHP gettext/Gettext_PO consumer) reads standard .mo files. Drop the compiled file into your theme's or plugin's languages/ folder using its expected <textdomain>-<locale>.mo filename.

I need to go the other way, from a compiled .mo back to editable .po

That's a separate decompile step — a MO to PO tool is planned. In the meantime, most gettext-aware editors (Poedit, GNU gettext's own msgunfmt) can open a .mo file directly.

For editing other structured translation/config formats, see the Java Properties File Formatter.