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Trustample

Convert MP3 to SRT subtitles

Time-coded captions from any audio file — edit first, export clean SRT or VTT.

By Anubhav Jain, Trustample founder · Updated July 2026 · Claims verified against the live product

Free: 60 min per 30 days, files up to 30 min / 50 MB · Paid plans: 10 to 100 hrs, files up to 2 GB. Big video? Upload just its audio track — same transcript, much faster upload.

Encrypted in transit · audio & video auto-delete in 30 days · never used to train AI

Optional settings

Set this for the most accurate result on quiet or mixed audio.

Get a second copy translated into another language (Pro).

Uncommon words the AI might misspell — list them so they come out right.

SRT is the universal subtitle format: video editors, YouTube, social platforms and media players all accept it. Trustample generates SRT straight from your audio, with cue timings taken from the AI's word-level timestamps.

Because you can edit the transcript before exporting, your subtitles ship correct — fix a name once in the editor and the exported SRT (and VTT for web players) carries the fix in every cue.

The typical job here is a podcast or voice-over that needs captions: the audio exists, the video is being assembled, and the editor wants a subtitle track that drops in with correct timing. Upload the MP3, review the transcript against the synced player, export the SRT, and import it into your editor next to the same audio — the cues land where the words are spoken. Transcription starts free; SRT and VTT exports are part of the paid plans, from Basic at $12/month.

How it works

  1. 1Upload the MP3 (or any audio/video file).
  2. 2Review the transcript and click-edit anything the AI misheard.
  3. 3Export SRT for editors and platforms, or VTT for web video players.

Frequently Asked Questions (FAQs)

What's the difference between SRT and VTT?

Both carry the same cues. SRT is the older, universally supported format (uses commas in timestamps); VTT is the web-native standard used by HTML5 video players. Trustample exports both.

Will the subtitle timings match my video?

If the audio you upload is the same audio in the video (same start point), timings match exactly — cue times come from word-level timestamps, not guesswork.

Can I edit subtitles after exporting?

SRT and VTT are plain text — any editor can open them. But it's easier to fix words in Trustample before exporting, so every future export stays correct too.

Which platforms accept the SRT file?

YouTube Studio, Premiere Pro, Final Cut, DaVinci Resolve, CapCut, VLC, Instagram (via editors) — effectively anything that supports external subtitles.

Is converting MP3 to SRT free?

The transcription is — 60 free minutes a month with the full editor. The SRT/VTT file export itself is a paid-plan feature (from Basic). If you already have a subtitle file and just need SRT↔VTT conversion or a line-length check, our standalone subtitle utilities are free with no signup.

My MP3 has long music sections. What happens to those?

Cues are generated where speech is detected, so music-only stretches simply produce no captions — which is usually what you want. If you need '[music]' markers for accessibility, add them in your video editor after import.

An honest note: Subtitle timing is only as precise as the speech is clear: mumbled or overlapping passages can produce cues you'll want to nudge a few frames in your editor. For clean narration and podcast audio, the export is typically usable as-is.

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