Free AI Subtitle Generators in 2026

Short answer: no free tier in the catalog burns captions into your video. What is free is the subtitle file (SRT or VTT) you then load into YouTube, Premiere, DaVinci Resolve or any editor. For code, AssemblyAI's $50 credit covers about 333 hours on Universal-2, Gladia's EUR 50 about 312 hours and Speechmatics gives $100; each returns SRT or VTT. For one file in a browser, Voxcribe's free plan (120 minutes a month, first file with no sign-up) gives the timed transcript as TXT, but SRT and VTT are paid there.

Five verified offers in the catalog can produce subtitles from audio or video, in two shapes: API credit you spend down (AssemblyAI, Gladia, Speechmatics, Deepgram) and a browser tool with a monthly allowance (Voxcribe). Every number below was read on the vendor's own pricing or docs page on 2026-11-10. For the transcription side alone, see the free speech-to-text API guide.

Compare the free subtitle generators #

The hours column is our arithmetic from each vendor's published per-hour rate; the vendors state the credit and the rate, not the hours.

Which one to pick #

• Most free subtitle hours: AssemblyAI ($50, 333 hours on Universal-2) or Gladia (EUR 50, 312 hours). Both export SRT and VTT directly.
• No code: Voxcribe for the transcript, then fix it in a text editor and time it yourself, or pay for its SRT. A free SRT without code needs an editor: Kapwing (auto-subtitling up to 10 minutes on its 10 free credits, 720p exports up to 4 minutes, with a Kapwing watermark) or Descript (60 media minutes a month, 720p export; watermark-free export is paid). Neither is in the catalog.
• Voiceover and video around it: the free AI voice generator guide, the free AI video generator guide and the free AI video tools hub.
• Editing the text of a video: free Descript alternatives compares the free transcription services.

Steps #

1. Export the audio track (MP3 or WAV) from your video; it uploads faster and costs the same as the video.
2. Sign up at AssemblyAI or Gladia, copy the API key and upload the file. In AssemblyAI, transcribe, then call the subtitles export (in the Python SDK, export_subtitles_srt with chars_per_caption=32 for readable lines). In Gladia, turn on the subtitles option and fetch the SRT or VTT.
3. At Speechmatics, request the transcript with format=srt on the transcript endpoint.
4. Open the SRT in your editor or upload it to YouTube, read it once for names and numbers, and fix them.
5. Keep captions short, two lines at most, so they stay readable on a phone.

Limits and the catch #

• AssemblyAI: the $50 credit is spent down by usage and does not refill; after it, pay-as-you-go applies.
• Gladia: the EUR 50 expires one year after sign-up and does not refill.
• Speechmatics: the $100 is valid 12 months and does not refill; Free allows 2 concurrent real-time sessions.
• Deepgram: the $200 is one-time credit; its docs show a WebVTT and SRT captions tutorial but the API itself returns JSON, so test the caption step before you rely on it.
• Voxcribe: SRT, VTT and DOCX are paid (plans from $9 a month, or a one-time 300-minute pack for $5).
• Accuracy: automatic subtitles need a read-through; names, numbers and overlapping speakers are where they go wrong.
• Free tiers change. Offers are re-checked monthly; the verified date on each offer page is the day we last confirmed it. The free AI audio tools hub lists every transcription offer we track.