Audio to Text
One page for any audio format
Drop MP3, M4A, WAV, FLAC, OGG, AAC, WebM and more. Get a clean transcript with timestamps, AI summary, and exports.
Drop your file here
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MP3 · MP4 · WAV · M4A · OGG · WEBM · FLAC · Max 25MB · Max 30 min
How it works
- 1
Drop any audio file
Upload from your device or drag and drop. MP3, M4A, WAV, FLAC, OGG, AAC, WebM, and more.
- 2
Whisper transcribes the audio
Whisper large-v3 runs on our backend with automatic punctuation, paragraph breaks, and per-segment timestamps.
- 3
Edit, export, share
Review the transcript, summarize with AI, translate to 50+ languages, and export as TXT, DOCX, PDF, or SRT.
Cleaner per-line layout with timestamps. Best for reading.
Why one audio-to-text tool is better
No convert-first step
Upload any audio format directly. Save time and keep your original quality, no lossy round-trip through a converter.
Automatic format detection
Mictoo detects the format from the file header and applies the best transcription settings for that codec.
Same accuracy across formats
Powered by Whisper large-v3 for consistent accuracy whether your file is MP3, WAV, FLAC, or WebM.
Summary and exports included
Get AI summaries, translate to 50+ languages, and export as TXT, SRT, VTT, or DOCX. No add-on plans.
When this page is the right fit
Mixed-format archives
One upload for all your files, whatever they were recorded on.
Unknown file format
Not sure what your recorder produced. We detect it and transcribe it.
Quick transcription
Fast results without setup, converters, or manual format picking.
Cross-tool workflows
Drop files exported from Zoom, Descript, Audacity, GarageBand, or any DAW.
First-time users
No signup, simple UI, free. A safe first try before committing to any tool.
Audio quality testing
Check clarity and see how much usable text you can get from a rough recording.
Audio quality matters more than file format
How Mictoo detects your format
1010
We read the file header (magic bytes) to identify your format instantly. This ensures the best settings for accurate transcription and means you never need to pick the format manually.
Supported audio formats
| Format | Common source | Best for | Direct upload |
|---|---|---|---|
| MP3 | Recorders, podcasts, downloads | General use, small files | |
| M4A | iPhone Voice Memos, Apple apps | High quality, efficient size | |
| WAV | Recordings, DAW exports | Uncompressed, pro audio | |
| FLAC | Music archives, high fidelity | Lossless quality | |
| OGG | Open source recordings, apps | Web and streaming | |
| AAC | Mobile recordings, streaming | Balanced quality and size | |
| WebM | Web recordings, browsers | Online video and audio |
What to know about each format
None of these need converting before upload. The notes below are the things that actually catch people out, per format.
MP3
The default for recorders, podcast downloads and anything shared over chat. Lossy, small, and universally readable.
- What we accept
- Any bitrate from 32 kbps up, mono or stereo, CBR or VBR. No re-encode before transcription
- Bitrate and accuracy
- Above roughly 64 kbps for speech, more bitrate stops helping. Whisper resamples to 16 kHz mono internally anyway
- Variable bitrate
- VBR files sometimes report the wrong duration in older players. That does not affect the transcript or the timestamps
- ID3 tags
- Ignored during transcription. The transcript comes back as plain text, so keep your episode metadata mapping in your own system
M4A
Not a codec but a container: AAC audio, occasionally ALAC, inside an MP4 wrapper. This is what an iPhone gives you.
- How we read it
- We parse the ftyp box, pull the AAC track, and hand it to Whisper without re-encoding
- Where it comes from
- iPhone Voice Memos, GarageBand, FaceTime, Apple Podcasts downloads
- From an iPhone
- Share the memo, save to Files or iCloud, then upload. No conversion step needed
- ALAC inside
- Some .m4a files hold Apple Lossless instead of AAC. Both work here, and neither needs converting first
WAV
Uncompressed PCM. The biggest files you will upload, and the cleanest source, though room noise still matters more than the format.
- What we accept
- 16, 24 and 32-bit PCM, any sample rate, mono or stereo, plus Broadcast Wave (BWF)
- BWF metadata
- bext and iXML chunks carrying timecode, scene and take are read past, not choked on. They do not appear in the transcript
- Size warning
- About 10 MB per minute at CD quality, so a 25-minute stereo recording already exceeds the anonymous limit
- Shrink it first
- Exporting mono at 64 kbps loses nothing for speech and cuts the file 10 to 15 times
FLAC
Lossless compression, roughly half the size of the same WAV. Common in oral-history archives and field-recording workflows.
- What we accept
- Native FLAC (magic bytes fLaC) and FLAC inside an OGG container, mono or stereo, up to 192 kHz, 16 or 24-bit
- No conversion needed
- The file goes straight through. Converting to MP3 first would only lose information
- Vorbis comments
- Ignored during transcription. If your archive relies on those tags, keep the mapping outside the transcript
- Worth the size?
- For accuracy, no. FLAC and a decent MP3 transcribe the same. Keep FLAC as the preservation copy, not because Whisper needs it
WEBM
A Matroska container, usually holding Opus audio, sometimes Vorbis. This is what browsers and screen recorders produce.
- Where it comes from
- Loom, OBS, the browser MediaRecorder API, Google Meet exports, YouTube downloads
- Video inside?
- We demux, drop the video track and transcribe the audio. Nothing to extract on your side
- Codecs
- Opus on anything recent, Vorbis on older files. Both handled without conversion
- Why the file is big
- Screen recordings are mostly video. A 20 MB WEBM often carries only 3 or 4 MB of audio
Frequently asked questions
What audio formats can I upload?
MP3, M4A, WAV, FLAC, OGG, AAC, WebM, MP4, MOV, plus AIFF, AU, OPUS, and MPEG. If your file plays in a normal media player, Mictoo can transcribe it. Video files are accepted too, we extract the audio track server-side.
How long does transcription take?
Usually seconds. A 10-minute audio file finishes in around 15 to 30 seconds; a 60-minute podcast is done in about a minute. Longer files that get auto-split take slightly longer as chunks are transcribed in parallel and merged.
Is audio transcription really free?
Yes. Free transcription up to 25 MB per file with no signup. A free account raises the per-file limit to 60 MB, and files up to 180 MB are auto-split into chunks and merged into a single transcript. No credit card, no hidden fees.
Are my audio files stored?
No. Files are streamed directly to the speech recognition provider (Groq for speed, with Replicate, Deepgram, and OpenAI as fallback), processed, and then deleted. Mictoo does not retain audio and providers do not train on API data.
Does file format affect accuracy?
Audio quality matters far more than format. Clean speech in a compressed MP3 will transcribe better than noisy audio in an uncompressed WAV. Mictoo runs the same Whisper large-v3 model on every format so accuracy stays consistent across all supported types.
Do I need to convert my audio to a specific format first?
No. That is the whole point of this page. Upload whatever your recorder, DAW, phone, or download tool produced. We detect the format from the file header and route it to Whisper directly. No converter step, no quality loss.
Can I edit the transcript before downloading?
Yes. After transcription, switch to the Editor view to fix any wrong names or jargon. Both Reader (per-line timestamps) and Editor (plain text) modes are available. Exports use whichever version you last edited.
How many languages does the transcription support?
Over 50 languages including English, Spanish, French, German, Portuguese, Russian, Ukrainian, Japanese, Chinese, Arabic, and many more. Auto-detect works for most files, or you can pick the language manually in the upload form for short clips.
Can I translate the transcript?
Yes. After transcription, click Translate and pick from 28 target languages. The translation is available in the Reader view and in every export format. Timestamps are preserved so the translated SRT still matches the audio.
What export formats are available?
TXT (plain text), SRT (subtitles), timestamped TXT, and DOCX (Word document). Registered users also get PDF, VTT (web captions), and JSON. All exports available from the Download menu after transcription finishes.