Free Audio to SRT Tool

AudioSRT is a free audio to SRT tool — a browser-based converter and subtitle editor in one. It transcribes MP3, WAV, M4A, OGG and video files to SRT using OpenAI Whisper running locally — no upload, no account, no file size or duration limit. After transcription, a built-in subtitle editor lets you fix timing, split lines, style subtitles with custom fonts and effects, and export to SRT, VTT, Premiere Pro JSON, or burned MP4. Cloud AI with 100+ language support is available on Starter.

What is an SRT file and why use it?

An SRT (SubRip Subtitle) file is the most widely supported subtitle format in the world. It's a plain text file containing numbered subtitle entries, each with a precise timestamp range and the caption text that should appear during that window. Every major video platform — YouTube, Vimeo, Netflix, Amazon — accepts SRT files, as do virtually all professional video editors including Premiere Pro, DaVinci Resolve, and Final Cut Pro.

SRT files separate your subtitles from your video, which means you can update captions without re-exporting the video, add multiple language tracks, and share caption files independently of the media. For creators who need accessibility compliance or simply want to maximise watch time (captions increase average view duration by up to 40%), starting with a good SRT file is the right foundation. AudioSRT makes it straightforward to convert audio to subtitles and get a publish-ready SRT without leaving the browser.

Supported audio formats

AudioSRT accepts all common audio formats without conversion:

• MP3 — the most common podcast and music format
• WAV — uncompressed audio from recording software
• M4A — Apple's audio format, common from iPhone recordings and GarageBand
• OGG — open-source format common from Audacity exports
• FLAC — lossless audio, often from audio interfaces and professional recordings
• AAC — high-quality compressed audio used by streaming platforms

Video files (MP4, MOV, WebM) are also supported — AudioSRT extracts the audio track automatically. There is no file size or duration limit on any format.

Step-by-step: audio transcription to SRT workflow

1. Open AudioSRT at audiosrt.com/tool. No account required. The tool loads entirely in your browser — this is your audio caption generator, subtitle editor, and SRT exporter in one place.
2. Drop your audio file onto the upload area, or click to select it from your file system. The file is read locally — nothing is sent to any server.
3. Wait for transcription. Whisper AI processes your audio in 30-second segments. A 10-minute file typically takes 2–4 minutes on a modern laptop. You can watch the transcript appear in real time as each segment completes.
4. Review the transcript. Click any word to correct it. The editor highlights the word you're editing and shows its timestamp so you can verify timing accuracy.
5. Split long subtitle lines. If any subtitle is too long for a single screen line, use the split control to divide it at the midpoint. The timestamps are recalculated proportionally.
6. Adjust styling (optional). Use the right panel to set font, size, colour, shadow and position. Changes are reflected instantly in the live preview.
7. Export SRT. Click Export and choose SRT. Your file downloads immediately — no rendering, no queue, no wait.

Tips for accurate transcription

Whisper AI is highly accurate but audio quality significantly affects results. A few practices that consistently improve accuracy:

• Use a close-field microphone rather than a laptop's built-in mic
• Record in a quiet environment — background noise reduces word recognition accuracy
• Speak at a moderate pace; very fast speech is harder for any AI to segment correctly
• For music-heavy content or audio with heavy reverb, cloud AI (Starter tier) handles noise better than the browser model
• If you're transcribing a recording with multiple speakers, consider splitting it into single-speaker segments first

When to use browser AI vs cloud AI

The free browser-based Whisper model is the right choice for most use cases: single speaker, English-language audio recorded in reasonable conditions. It is completely private, has no usage limits, and requires no account. If you want to generate subtitles from audio without any cloud dependency, this is the tier to use.

Upgrade to Starter (Deepgram Nova-3) when you need: faster turnaround (cloud AI is up to 30× faster than browser), non-English languages (100+ supported), or higher accuracy on noisy or multi-speaker audio. Starter gives you unlimited cloud transcription — the same subtitle editor and SRT export, just significantly faster audio transcription to SRT.

Common mistakes when creating SRT files

Even with accurate transcription, SRT files often need cleanup before they're ready to use. The most common issues:

• Lines that are too long. SRT subtitles should ideally be no more than 42 characters per line and two lines maximum. Longer lines may be cut off on smaller screens.
• Subtitle duration mismatches. A subtitle displayed for 6 seconds covering only 3 words feels slow; one displayed for 0.5 seconds covering 12 words is unreadable. AudioSRT's editor lets you adjust start and end timestamps directly.
• Speaker attribution missing. If your audio has multiple speakers, it can help to prefix subtitles with the speaker name in brackets: [Host] or [Guest].
• Overlapping timestamps. SRT files with overlapping start/end times cause undefined behaviour in some players. AudioSRT's export validates timestamps automatically.