PO to MO Converter
Compile a GNU gettext .po translation source file into a binary .mo file, ready for PHP, Python, WordPress, or any gettext-based app. Runs entirely in your browser — no upload.
Input
Read as UTF-8 text and dropped straight into the box above.
Output
More ways to use this tool
REST API
curl -X POST https://api.iotools.cloud/v1/tool/po-to-mo \
-H "Authorization: Bearer YOUR_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"po": "#\nmsgid \"\"\nmsgstr \"\"\n\"Content-Type: text/plain; …"
}'Swap in your own key from your account. The tool's fields are the body — no wrapper.
Ask an AI agent
Use the IOTools `po-to-mo` tool (PO to MO Converter) on this input:
YOUR_INPUT_HEREPaste this at any agent connected to the IOTools MCP server, then add your input.
Embed widget
<iframe
src="https://iotools.cloud/embed/po-to-mo/"
width="100%" height="520" frameborder="0" scrolling="no" loading="lazy"
title="PO to MO Converter — iotools.cloud"
sandbox="allow-scripts allow-forms allow-same-origin allow-downloads allow-popups allow-popups-to-escape-sandbox"
allow="clipboard-write"
style="width:100%;border:1px solid #e5e7eb;border-radius:12px;overflow:hidden"></iframe>
<script src="https://iotools.cloud/embed.js" async></script>Drop this into your own page — free, no key required, just a link back.
| Cost per API/MCP call | From 5 credits |
|---|---|
| Need more credits? | View pricing |
Also available with
Guides
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/msgstrsplit across several quoted lines is joined back together, same asmsgfmt. - Plural forms —
msgid_pluraland indexedmsgstr[0],msgstr[1], … are compiled into gettext's NUL-joined binary plural encoding, songettext()/_n()lookups work correctly. - Message contexts — a
msgctxtis folded into the compiled key exactly aspgettext()/_x()expect. - Fuzzy and untranslated entries are skipped, matching
msgfmt's default behavior (no--use-fuzzy). A string flagged#, fuzzyis 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 bymsgmergewhen 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
Use the MO to PO Converter — the exact inverse of this tool, also entirely client-side.
For editing other structured translation/config formats, see the Java Properties File Formatter.