Free tool

Opus to text converter

Drop an .opus file here to change Opus to text: the converter decodes the Opus sound in your browser and returns a transcript with a time on every paragraph, ready to copy into a reply or save.

  • Free
  • Tiny voice notes welcome
  • Nothing is stored

Choose your Opus file

MP3, M4A, WAV, AAC, FLAC, OGG or WebM. Up to 30 minutes of each file, 3 free files a day. The language is detected automatically.

Rather speak than type? NoteOwl’s free dictation turns your voice into text in any Mac app, and NoteOwl transcribes saved .opus files there with unlimited transcription.

Download free for MacSend to my Mac

How it works

How do you transcribe an Opus file?

Choose the .opus file or drag it onto the converter. Your browser decodes the Opus sound, the page cuts it into short pieces where the speaker pauses, and AI transcription writes each one. The transcript builds up in order, with times.

  1. 1

    Choose the .opus file

    A WhatsApp voice note copied off an Android phone, or any other Opus recording. Files ending .ogg with Opus inside work the same way.

  2. 2

    Read it as it transcribes

    Each paragraph is labelled with the moment it begins. Recordings are transcribed up to their first 30 minutes.

  3. 3

    Save the words

    Copy the transcript into a message or a note, or download TXT, SRT, VTT or Word.

What is an Opus file?

Opus is an open audio codec, standardised in 2012 and built to keep voices clear at low bitrates. A file ending in .opus is an Ogg file with Opus sound inside. WhatsApp, Telegram and calls made in a browser all use Opus.

WhatsApp on Android, voice notes in phone storage
File you get.opus
WhatsApp Web, a downloaded voice message
File you get.ogg
Telegram voice messages
File you get.ogg
Chrome or Edge recording a microphone
File you get.webm

Why is an Opus voice note so small?

Because Opus needs very few bits to carry speech. In our test, a minute of mono voice at 16 kbps took about 0.1 MB, around a twentieth of the same minute as a 16 kHz WAV. The converter decodes it into ordinary 16 kHz audio before transcribing.

Where does WhatsApp keep .opus files on Android?

In the phone’s own storage, in a folder called WhatsApp Voice Notes that is split into subfolders by date. Open it with a file manager, or connect the phone to a computer with a USB cable and copy the notes across.

  1. 1

    Open the storage

    Use the Files app on the phone, or open the phone’s storage from a computer over USB.

  2. 2

    Follow the path

    Android › media › com.whatsapp › WhatsApp › Media › WhatsApp Voice Notes.

  3. 3

    Pick by date

    Each note is named PTT, then the date it was sent, such as PTT-20261015-WA0003.opus.

Do you need to rename an .opus file to .ogg?

No. The converter identifies an Opus file by its contents, not its name, so .opus, .ogg and .oga files all open as they are. Even a voice note saved with the wrong ending is recognised.

Want Opus files transcribed on your Mac instead?

NoteOwl imports .opus and .ogg recordings and transcribes them on your Mac with unlimited transcription and on-device AI models. Its dictation is free and types what you say into any app, so you can skip the voice note altogether.

FAQ

Questions about Opus to text

Is the Opus to text converter free?

Yes. There’s no sign-up: transcribe 3 Opus files a day, up to 30 minutes of each, and copy or download every transcript.

Can it transcribe a WhatsApp voice note?

Yes. On Android, WhatsApp keeps voice notes as .opus files; WhatsApp Web downloads them as .ogg files. Both hold the same Opus sound, and the converter can convert Opus to text from either one.

Can it read Opus sound inside a WebM file?

Yes. Recordings made in Chrome or Edge are usually WebM files with Opus sound, and the converter takes the sound out of them the same way, with or without a video track.

What happens to my Opus file?

It isn’t uploaded as a file. Your browser decodes it and sends short pieces of the sound, over a secure connection, to a cloud AI transcription service, which transcribes each piece and discards it. NoteOwl keeps no audio and no transcript.

Which browsers can open .opus files here?

In our tests, .opus files in mono and stereo decoded in Chrome, Edge and Safari 26 on a Mac. Use a current version of your browser, since older ones may lack an Opus decoder.

Can it transcribe a voice note in another language?

Yes. The converter works out the language of each part of the note by itself and names the main one with the transcript. A note that switches language is written in each language as it goes.

What if the Opus recording is longer than 30 minutes?

Its first 30 minutes are transcribed and the page says where it stopped. Cut the file into parts for the rest, or import it into NoteOwl on a Mac, which has no length limit.

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About NoteOwl

NoteOwl is private AI meeting notes and memory for the Mac. It captures meetings without a bot joining the call, labels every speaker, writes summaries and action items, and builds a memory of every conversation that you can chat with — fully offline, because the speech recognition and the AI run on the Mac itself. Dictation into any app is free; Pro is a one-time purchase.

NoteOwl pricing: what’s free and what Pro adds

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