What is an .opus file?

Opus is the audio format WhatsApp uses for voice notes. It keeps speech clear at a very small file size, which is why a minute of voice note weighs only a few hundred kilobytes.

Where do I find the .opus files?

Export the chat with media. The .zip contains one .opus file per voice note: named PTT-20260301-WA0004.opus on Android and 00000046-AUDIO-2026-03-01-14-23-02.opus on iPhone.

Can I transcribe a single .opus file?

Zap2Doc needs a WhatsApp chat export ZIP, not a standalone .opus file. Export the conversation with media to keep the sender, date and time with the transcript.

Which languages work?

Zap2Doc detects the language of each voice note by itself, so a chat that mixes languages is transcribed note by note.

WhatsApp .opus File to Text: How to Transcribe Voice Notes

WhatsApp voice notes are .opus files. What the format is, how to play one, and how to turn one voice note, or every voice note in a chat, into text with the date and sender of each.

Voice notes transcribed under their messages

Every WhatsApp voice note is an .opus file. You’ll meet them when you export a chat with media, or when someone forwards you a voice note as a file. Most apps on your computer won’t open them, and none of them show you the words.

What .opus is #

Opus is an open audio format built for speech over the internet. WhatsApp uses it because a voice note stays clear at a tiny size: about 2 KB per second.

In an export, the voice notes are named by phone:

Android: PTT-20260301-WA0004.opus (PTT stands for push-to-talk).
iPhone: 00000046-AUDIO-2026-03-01-14-23-02.opus.

Audio files sent through the chat (not recorded in it) keep their own format, such as .m4a or .mp3. Those are covered in WhatsApp audio files to text: m4a, aac, amr and mp3.

How to play one #

VLC plays .opus on Windows, Mac, Android and iPhone.
Chrome and Firefox play a .opus file dragged into a tab.
On a Mac, QuickTime often refuses it; use VLC or a browser.

Turning .opus into text #

There are two ways, depending on what you need.

One voice note. Any general transcription tool that accepts .opus can do it. You get the words, but nothing else: the file name is the only clue to who sent it and when.

Every voice note in a chat. This is where the export earns its keep. The chat’s text file records exactly when each voice note was sent and by whom. Reading the export as a whole puts every transcript back under its message.

Transcribing a whole chat with Zap2Doc #

Zap2Doc accepts the original WhatsApp chat ZIP containing the conversation text and audio, not a standalone .opus upload. For several voice notes, follow transcribing the whole chat.

Export the chat with media from WhatsApp (Android, iPhone).
Upload the .zip to Zap2Doc. It finds every .opus file and measures how much audio the chat has.
See the free preview, then download a chronological PDF where every voice note is transcribed under its sender, date and time, with the photos in place.

Up to 2 hours of audio is included in the base price; for longer chats, the preview shows the price before you pay. Silent voice notes are marked as having no speech rather than left blank.