MP3 to SRT Converter
Convert MP3 audio files to accurate SRT subtitles free. Whisper AI runs in your browser — your MP3 never leaves your device.
Drop your audio or video file here
MP3, WAV, M4A, MP4, MOV, WebM · Any size
Click any word to correct it
MP3 is the world's most common audio format — but most subtitle tools make you upload it to a cloud server.
Podcast episodes, recorded interviews, voice memos — MP3 files often contain sensitive content. AudioSRT converts MP3 to SRT entirely in your browser. No upload. No storage. No privacy risk.
Who is this for?
- Podcasters creating episode transcripts and subtitles
- Journalists transcribing recorded interviews
- Students converting lecture recordings to searchable text
- Anyone converting voice memos to written subtitles
From MP3 file to finished SRT in minutes.
Upload MP3
Drop your MP3 file into AudioSRT. Any bitrate, any size.
AI Transcribes Locally
Whisper AI runs entirely in your browser. Your file never leaves your device.
Edit Subtitles
Fix any errors, split long lines, and adjust timing in the built-in editor.
Export SRT
Download your SRT file — or export as VTT, TXT, or Premiere Pro JSON.
Everything you need to convert MP3 to SRT.
Any MP3 Bitrate
Works with 128kbps, 192kbps, 256kbps, 320kbps — any bitrate your MP3 uses.
No File Size Limit
No cap on file size or duration. Long-form podcast episodes and interviews process without issue.
Built-in Subtitle Editor
Edit text, timing, and line breaks without switching tools. Everything in one place.
Multiple Export Formats
Export as SRT, VTT, plain text, or native Premiere Pro JSON — all from the same transcription.
Why AudioSRT
Upload MP3 to cloud server
Transcribe locally, zero upload
Per-minute charges for long audio
No cost regardless of duration
Export only SRT
SRT, VTT, TXT, Premiere JSON
Complete guide: Converting MP3 to SRT subtitles
MP3 (MPEG Audio Layer III) is the most widely used audio format in the world — and AudioSRT converts MP3 files to accurate SRT subtitles entirely within your browser, without uploading anything. Whether you're subtitling a podcast episode, transcribing an interview, or captioning a recorded lecture, this guide covers everything you need to know.
What is MP3 and why is it the most common audio format?
MP3 compresses audio by removing frequencies that the human ear is least sensitive to — a technique called perceptual coding. This dramatically reduces file size (typically 10:1 compression ratio over uncompressed WAV) while retaining audio that sounds natural to most listeners. An hour of uncompressed 16-bit stereo audio at 44.1kHz takes around 635MB as WAV; at 128kbps MP3, the same hour is about 57MB.
Because of this compression efficiency, MP3 became the standard for digital audio distribution in the late 1990s and has remained dominant for podcasts, voice recordings, and music ever since. Nearly every recording device, phone, and software platform can produce and play MP3 files.
How MP3 bitrate affects transcription accuracy
MP3 bitrate determines how much audio data is retained per second. Higher bitrate = more audio information = better quality = higher transcription accuracy. Here's what to expect:
- 320kbps: Near-lossless quality. Whisper AI performs at its ceiling — accuracy equivalent to uncompressed audio for most speech content.
- 192kbps: Excellent for speech. Minimal audible compression artifacts. High transcription accuracy.
- 128kbps: The most common podcast and voice memo bitrate. Transcription accuracy is still very high for clear speech.
- 64kbps and below: Compression becomes audible. Accuracy drops, particularly for proper nouns, technical terms, and overlapping speech.
For new recordings, capture at the highest bitrate your recorder supports. For existing MP3 files, AudioSRT will handle whatever bitrate you have — but don't re-encode a low-quality MP3 at higher bitrate expecting better results. Re-encoding cannot recover data that was discarded during original compression.
Why browser-based MP3 transcription protects your privacy
Most cloud transcription services — including many well-known ones — retain uploaded audio for model training, quality review, or compliance purposes. When you upload a podcast interview, a legal recording, or a private voice memo to a cloud service, you're handing over that content to a third party. Many privacy policies allow retention for 30–90 days; some longer.
AudioSRT uses Whisper AI compiled to WebAssembly, running entirely inside your browser tab. Your MP3 is read from disk into browser memory, processed by the WebAssembly Whisper model, and the transcript is written to the page — all locally. Nothing is transmitted to AudioSRT's servers during this process. When you close the tab, the audio data is gone.
Workflow tips for accurate MP3 transcription
Transcription accuracy depends heavily on recording quality. For the best results with MP3 files:
- Use a decent microphone. Built-in laptop mics in noisy environments produce far more errors than a $50 USB mic in a quiet room.
- Keep background noise low. HVAC noise, street sound, and room echo all reduce accuracy. If you have a noisy recording, try Whisper's noise suppression setting in AudioSRT.
- Set language explicitly. If your podcast is in a specific language, select it before transcribing rather than relying on auto-detect. This reduces errors on language-boundary words.
- Transcribe at speed 1.0x. Some tools let you pitch-shift audio before transcription. Don't. Whisper is calibrated for natural speech speed.
Exporting subtitles from MP3 transcription
After transcribing your MP3 and editing the subtitles in AudioSRT, you can export in multiple formats:
- SRT — the universal subtitle format. Works in VLC, video editors, YouTube, Vimeo, and virtually every platform that accepts subtitle files.
- VTT (WebVTT) — required for HTML5 web video. Use this if you're embedding video on a website with the
<track>element. - Plain text — timestamps stripped, text only. Useful for creating written transcripts, blog posts, or show notes.
- Premiere Pro JSON — native caption tracks for Adobe Premiere Pro. Imports as editable caption tracks, not a static SRT layer.
Frequently asked questions
Can I convert MP3 to SRT without uploading?
Yes — AudioSRT uses Whisper AI compiled to WebAssembly running in your browser. Your MP3 is never uploaded to any server. Transcription happens entirely on your device.
What MP3 bitrates does AudioSRT support?
All standard MP3 bitrates are supported: 32, 64, 96, 128, 160, 192, 224, 256, and 320kbps. Variable bitrate (VBR) MP3s also work. Higher bitrates generally yield better transcription accuracy.
Is there a file size limit for MP3 files?
No. AudioSRT has no file size or duration limit. Long-form podcast episodes and multi-hour interview recordings process the same as short clips.
How accurate is MP3 to SRT transcription?
For clear speech at 128kbps or higher, Whisper AI typically achieves 95%+ word accuracy. Accuracy decreases with background noise, heavy accents, multiple overlapping speakers, or very low bitrate (below 64kbps) recordings.
Can I edit the subtitles after transcription?
Yes — AudioSRT includes a full subtitle editor. You can fix text, adjust timestamps, split or merge lines, and change styling before exporting.
What formats can I export after converting MP3 to SRT?
SRT, VTT (WebVTT), plain text transcript, and Premiere Pro JSON are all available from the same transcription. You don't need to re-transcribe for each format.
Does AudioSRT support MP3 files from iPhone or Android?
Yes. Voice memos and audio recorded on phones are typically MP3 or M4A — both are supported. Drop the file directly from your phone's export or after AirDrop/USB transfer to your computer.