Add subtitles to an audio file. Upload MP3 or WAV, pick a background, and get a video with timed captions you can post anywhere sound is off.
Free for recordings up to 1 hour and 1 GB. Longer files need a paid plan.
How It Works
Drop an audio or video file — MP4, MOV, MP3, WAV, M4A and more. The language is detected automatically.
AssemblyAI transcribes every word with exact timings — usually a fraction of the recording's length.
Copy the text or download SRT, VTT and TXT files.
The Add Subtitles to Audio is a free online tool from ShortsHero: turn an audio file into a captioned video. AssemblyAI speech recognition does the work — a 5-minute recording usually comes back in under 30 seconds. It is free for files up to 1 hour with no watermark; longer recordings need a paid plan.
Free transcription covers files up to 1 hour. If your recording is longer, a paid plan lifts the limit — or trim it into parts and run each one.
Why Use This Tool
Every word carries its start and end time, so subtitles line up with the speech.
The formats YouTube, Premiere, Resolve, CapCut and every major player accept.
Filter the transcript on the page to find any word and jump to its timestamp.
Full recordings, not a one-minute sample. Paid plans lift the length limit.
The spoken language is detected automatically.
Use the files anywhere — the transcript and subtitles are yours.
Yes. Files up to 1 hour long are free, with no watermark and no account needed. Recordings longer than 1 hour need a paid ShortsHero plan.
MP4, MOV, WebM, MKV, MP3, WAV, M4A, AAC, OGG, FLAC and most other audio and video formats, up to 1 GB. For a long video, uploading just the audio is faster.
Yes. Download the SRT and open it in our free online SRT editor, or in any video editor, to fix a word or a timing.
Usually well under the length of the recording — a 10-minute file is typically done in about a minute.
ShortsHero turns long videos into short vertical clips with AI moment detection, face tracking and animated captions — and has free tools for subtitles, transcripts and video formats.
The same transcription powers ShortsHero's clip maker: it finds the strongest moments, reframes them to vertical and adds word-by-word captions in 36 styles.
Try the clip maker freeFree to start · No credit card required
Keep Going
Upload once and get subtitle files in many languages at the same time. Pick up to 20 languages and download a zip of SRT files ready for YouTube.
Generate animated captions where every word highlights as it's spoken. Pick a style, upload your video, export with captions burned in.
Get Alex Hormozi style captions on any video: big bold words, a few at a time, with key words in colour. Upload and export in minutes.
Add MrBeast style captions to your video: heavy outline, bouncy pop-in and bright colours. Upload a clip and export it captioned in 1080p.
Burn subtitles into a video online. Upload the video and your SRT file and get one MP4 with the captions permanently on screen. Free.
Convert SRT to TXT instantly. Removes numbers and timestamps and joins the lines into a readable transcript. Runs in your browser, nothing uploaded.