Video caption / subtitle generator
Generate accurate captions for short-form video based on a script or transcript paste.
about the video caption / subtitle generator
The large majority of social video is watched on mute — people scroll in offices, commutes, and waiting rooms with the sound off. If your short-form video relies on audio alone, most viewers swipe past before they ever hear your hook. On-screen captions are the fix: they're consistently shown to lift watch time and completion rates, and they make your content accessible to deaf and hard-of-hearing viewers at the same time.
Good video captions follow readability rules: 1-2 short lines on screen at a time (roughly 32-42 characters per line), synced tightly to speech, positioned in the platform's safe zone so TikTok, Reels, and Shorts UI elements don't cover them, and broken at natural phrase boundaries rather than mid-clause. Burned-in styled captions have also become an aesthetic of their own — the bold word-by-word style popularized by top short-form creators reinforces the hook visually.
Paste your script or transcript and the generator returns clean, properly segmented captions ready to drop into your editor or upload as a subtitle file. Once your captioned video is exported, schedule it to TikTok, Reels, and YouTube Shorts in one pass with PostAI instead of uploading to each app manually.
frequently asked questions
Why do social media videos need captions?
Because most social video is watched with the sound off — viewers scroll in public and only unmute when already hooked. Captions keep muted viewers watching, improve completion rates, and make content accessible to deaf and hard-of-hearing audiences. Platforms also index caption text, which can help discovery.
How many characters per line should video subtitles be?
Keep lines to roughly 32-42 characters, with a maximum of two lines on screen at once. Break lines at natural phrase boundaries, not mid-clause, and keep each caption on screen long enough to read — about 1-3 seconds for a short line. Short-form styles often go further, showing just 3-5 words at a time.
What is the difference between captions and subtitles?
Subtitles transcribe only spoken dialogue, usually for viewers who don't speak the language. Captions (closed or burned-in) additionally convey non-speech audio like music and sound effects, serving viewers watching without sound. For short-form social video, burned-in captions are standard because they display regardless of the viewer's settings.
want to schedule and post, not just format?
PostAI schedules to 11 platforms, includes AI content generation, and starts at $9/mo.
start free — no credit card