Any audio format · Free · No signup

Audio to Text
One page for any audio format

The format-agnostic entry point. Drop an MP3, M4A, WAV, FLAC, OGG, AAC, WebM, or any other common audio file and get a clean transcript with timestamps, AI summary, and exports for TXT, SRT, VTT, and DOCX.

AI summaryTranslate, 28 langsOpenAI Whisper

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MP3 · MP4 · WAV · M4A · OGG · WEBM · FLAC · Max 25MB · Max 30 min (60 min · Sign in)

Got a bigger file? See how to compress.

Got a longer recording? See how to split.

Most transcription services nudge you to convert your audio to one specific format first ("upload an MP3", "use WAV only"). Mictoo does not. We accept whatever your recorder, DAW, phone, or download tool produced and handle the format details on our side.

Useful when you have a folder of mixed formats (Voice Memos in M4A, GarageBand bounces in WAV, downloaded podcasts in MP3) and just want to transcribe them without running each through a converter first.

If you know your format and want format-specific guidance:WAV,M4A,FLAC,OGG,AAC,WebM pages cover the specifics.

How it works

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Drop any audio file

MP3, M4A, WAV, FLAC, OGG, AAC, WebM, AIFF, AU, plus several rarer formats. We auto-detect what you uploaded from the file header, no manual format picker needed.

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Whisper transcribes the audio

A 30-minute file usually finishes in 30-60 seconds. We route through Whisper large-v3 via Groq, with Replicate, Deepgram, and OpenAI as fallback providers for reliability.

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Edit, export, share

Inline editor for fixing wrong names. Download TXT, SRT, VTT, or DOCX. Translate to 50+ languages with one click. AI summary appears alongside automatically.

Why a format-agnostic transcription tool helps

No "convert first" step in your workflow

You have an iPhone Voice Memo (M4A), a GarageBand bounce (WAV), and a podcast download (MP3). Three different formats, one upload page. No detour through a format converter, no decision about which input is "correct".

Automatic format detection from file headers

We read the file header to determine the actual format, not just the extension. A file someone renamed .mp3 that is actually AAC inside still works. Files with no extension still work as long as the header is intact.

Same accuracy regardless of source format

Whisper resamples everything to 16 kHz mono internally before transcription. WAV, MP3, M4A, FLAC, all produce the same transcript quality for clean audio. Format only matters for upload size and storage convenience, not for transcription accuracy.

AI summary, translation, and exports built in

Once the transcript finishes, an AI summary appears alongside. Translate to another language with one click. Download as TXT, SRT, VTT, or DOCX. Everything in one workflow, no plan tier to unlock features.

Free for files up to 60 MB

No signup, no watermark, no daily file counter. 60 MB covers most everyday recordings (60 minutes of mono speech, 30 minutes of typical stereo podcast, 15 minutes of high-quality WAV). For larger files, see the Pro tips section.

When the format-agnostic page is the right fit

Mixed-format archive cleanup

Inherited a folder of old recordings in mixed formats (.wav from one device, .m4a from another, .mp3 downloads). Process them through one page without sorting by format first.

Quick transcription, format unknown

Someone sent you an audio file and you have not checked what format it is. Drop here, find out as it processes. Saves the "open in QuickTime, check Inspector" step.

Cross-tool workflows

Recording in Audacity (WAV), exporting from GarageBand (M4A), downloading from Bandcamp (FLAC). Different tools produce different formats. One transcription page handles them all.

First-time transcription users

New to transcription tools and unsure which "format-specific" page to use. The audio-to-text page is the safe default for any audio file.

Quick test of an unknown audio quality

Got a recording from someone with no context about quality or format. Drop here for a fast transcript that tells you whether the audio is clean enough to be useful.

Integration testing with multiple audio sources

Building a workflow that ingests audio from many sources (phone calls, recordings, downloads). Validate transcription works for each source format without setting up format-specific routes.

Format-agnostic tips that save time

For very large files, prefer audio-only formats

Video files (MP4, MOV, WebM) work, but they are much bigger than audio-only equivalents. If your source is a video, extract just the audio first with ffmpeg -i video.mp4 -vn -ac 1 -ar 16000 audio.m4a. The audio is typically 10-20x smaller.

Set the language manually for short files or non-English audio

Whisper auto-detects language but can mis-fire on clips under 30 seconds or files that open with music. For short clips or any non-English audio, pick the language explicitly in the dropdown before upload.

For format-specific gotchas, check the dedicated page

This page is the universal entry point. For format-specific advice (WAV settings, FLAC compression, M4A iPhone Voice Memo specifics), the individual format pages have deeper guidance.

Audio quality matters more than format choice

A clean MP3 at 64 kbps transcribes better than a noisy WAV at studio quality. Clean the audio (denoise, set mic close to speaker) before recording rather than picking a format and hoping it compensates.

What "audio format" actually means here

An audio format is a combination of a container (the file wrapper) and a codec (the algorithm that compresses or stores the audio inside). Most people use "format" loosely to mean both. WAV is a container with PCM codec (uncompressed). MP3 is a codec with no container (just the raw stream). M4A is an MP4 container with AAC codec inside. FLAC is both a codec and a container that share the same name. OGG is a container that usually holds Opus or Vorbis.

For transcription, what matters is that the audio data inside can be decoded to raw PCM samples that the Whisper model reads. We handle the container and codec details on our side, you just upload the file.

Why format choice almost never affects transcript quality

Whisper large-v3 resamples whatever audio it gets to 16 kHz mono before the first inference step. A 192 kHz 24-bit stereo studio recording gets crushed down to the same input shape as a 16 kHz mono phone call. The model never sees the "fancy" version of the audio.

What this means in practice: a 128 kbps MP3 of your podcast transcribes essentially the same as the original 24-bit WAV master. A 32 kbps Opus voice message from Telegram transcribes essentially the same as if you had recorded the same voice in WAV. The format only matters at the edges: very low bitrate compressed audio (under 32 kbps) starts to lose information Whisper needs.

When format actually does matter

For upload size and storage. A one-hour recording is around 14 MB as 32 kbps mono AAC, 30 MB as 64 kbps mono MP3, 300+ MB as CD-quality WAV. The transcript is the same; the upload time and storage cost are very different. For everyday use, small lossy formats (MP3, M4A, OGG) are the practical choice. For archival or editing, keep the original lossless format (WAV, FLAC, ALAC) on your drive.

How we handle format detection

On upload, we read the first few bytes of the file to identify the container and codec. Most audio formats have distinctive magic numbers in their headers: WAV starts with "RIFF", MP3 starts with "ID3" or specific frame sync patterns, M4A/MP4 starts with "ftyp", FLAC starts with "fLaC", OGG starts with "OggS". We use the header rather than the file extension because extensions can lie (a renamed file, a system that stripped the extension).

What we do not currently accept

Proprietary or encrypted formats with DRM. Some old WMA files from the Microsoft DRM era cannot be decoded by any current open-source tool. Apple-Lossless ALAC files inside DRM-protected M4P containers (legacy iTunes Store purchases before 2009) similarly cannot be decoded. For these cases, you need to find or generate an unprotected copy.

Frequently asked questions

What audio formats does Mictoo accept?

MP3, M4A, WAV, FLAC, OGG (with Vorbis or Opus codec), AAC, WebM, AIFF, AU, and several rarer formats. For video files (MP4, MOV, WebM video), we strip the video and transcribe just the audio. Free for files up to 60 MB.

Does the format affect transcript quality?

Almost never. Whisper resamples to 16 kHz mono internally before transcription, so format choice (MP3 vs WAV vs M4A) makes essentially no difference for clean audio. Format matters at extremes: very low bitrate (under 32 kbps) lossy formats can lose audio information Whisper needs.

Do I need to know my file format before uploading?

No. We detect the format from the file header during upload, not from the extension. Even a file with a wrong extension or no extension works as long as the header bytes identify a supported format.

What is the largest file I can upload?

Free tier: 60 MB per file. That covers 60 minutes of mono speech at typical bitrates, 30 minutes of typical stereo podcast, or about 15 minutes of CD-quality WAV. For larger files, use format-specific compression tips on the individual format pages.

Can I get the transcript in multiple formats?

Yes. TXT for plain text, SRT or VTT for subtitle files with timestamps, DOCX for a Word document. Or copy directly to clipboard. The transcript itself is the same; the export format just affects how it lands in your destination.

Does Mictoo transcribe non-English audio?

Yes. Whisper large-v3 supports 50+ languages with auto-detection. For short files or files that open with non-speech audio, set the language explicitly in the dropdown for cleaner first-pass detection.

Can I translate the transcript to another language?

Yes. After transcription finishes, pick a target language from the dropdown and click Translate. The translation is generated by GPT-4o-mini and appears alongside the original transcript.

Does my audio file get stored?

No. The audio streams to the transcription provider, gets processed once, and is dropped from memory. We do not write the audio to disk. The text transcript is only stored if you sign in and choose to save it to your history.

How long does transcription take?

Upload time plus processing time. A 30-minute audio-only file typically finishes in 30-60 seconds end to end on a normal home connection. Larger files (near the 60 MB cap) take 1-2 minutes total.

What if my file format is rejected?

Most likely the file is either DRM-protected (rare for audio in 2026), corrupted (header missing or partial), or a format we do not yet support. Check the file plays in a normal media player first; if it does, contact us with the file details so we can add support.