Short-form Caption Formatter

The Short-form Caption Formatter rewraps an SRT for vertical mobile video and hands back a valid SRT you can download with the .srt extension. Paste into SRT Content, choose a value for Max chars per line, optionally tick Uppercase, and every cue is rewrapped, capped at two lines and capitalised if asked. Timings are untouched.

Captions written for a 16:9 television do not survive on a phone held upright. Lines sized for 42 characters run off the frame or collide with the interface furniture Instagram, TikTok and YouTube Shorts stack over the bottom of the picture. Social editors and creators repurposing a webinar or podcast into vertical clips hit this every time, and hand-rewrapping a hundred cues is nobody's idea of a good afternoon.

The formatter parses the SRT into cues, uppercases first if Uppercase is ticked, then rewraps each line. Lines already within the limit are left alone; longer ones are split on word boundaries so words are never cut in half. The resulting lines are then truncated to the first two, which is what enforces the punchy look - so a very long cue can lose trailing text and should be split into separate cues first. Leaving Max chars per line empty uses 32.

Everything runs in the browser with no upload, so unpublished campaign copy never leaves your laptop.

• Adjustable line width: The Max chars per line field sets the wrap limit and defaults to 32 when left blank, so you can tighten to the high twenties for large caption styles or loosen it slightly for smaller type.
• Optional uppercasing: Ticking Uppercase converts all cue text to capitals before wrapping, which is the high-contrast look most short-form templates use and which measurably improves legibility on small screens.
• Word-safe wrapping: Splits happen only at spaces, so a word is never broken across two lines and captions never show a stray fragment mid-word.
• Two-line ceiling: After wrapping, each cue is limited to its first two lines, keeping the block short enough to sit clear of platform interface elements at the bottom of a vertical frame.
• Timings preserved exactly: Only the text of each cue is rewritten; start and end times are carried through unchanged, so your captions stay in sync with the edit.
• Valid SRT out: The result is renumbered, properly formatted SRT that you can download with the .srt extension and drop straight into a caption uploader or editing timeline.
• Short lines left alone: Lines already within the limit pass through untouched, so a partly formatted file is not needlessly rewrapped.
• Local processing: The rewrap happens entirely in your browser, so campaign scripts under embargo are never uploaded.

1. Paste the captions from your long-form edit into the SRT Content box, or press Load sample to see a typical over-wide cue.
2. Set Max chars per line to the width your caption style allows, starting at 32 and dropping to around 24 if your template uses very large type.
3. Tick Uppercase if your template calls for all-caps captions, or leave it clear to keep the original sentence case.
4. Press Run to rewrap the file, then scan the output for cues that look shorter than the source, since anything beyond two lines is dropped.
5. Split any cue that lost text into two shorter cues in your subtitle editor and run the formatter again.
6. Download the result as a .srt file and import it into your vertical edit or upload it to the platform's caption tool.
7. Preview a few captioned moments on an actual phone to confirm the lines clear the interface and are comfortable to read at arm's length.

Example 1 - rewrapping a wide broadcast line. A single 58-character line becomes two mobile-friendly lines with the timing untouched.

Input (Max chars per line: 32):
4
00:00:12,000 --> 00:00:15,500
We tested every single model in the range this week.

Output:
4
00:00:12,000 --> 00:00:15,500
We tested every single model
in the range this week.

Example 2 - the uppercase treatment. Ticking Uppercase applies capitals before wrapping, so the line breaks are calculated on the text as it will actually appear.

Output with Uppercase ticked:
WE TESTED EVERY SINGLE MODEL
IN THE RANGE THIS WEEK.

The cue now occupies two short lines that sit above a Reels caption bar instead of running off the edge, and the timings are identical to the source so nothing needs re-syncing.

• Captions that fit the frame: Rewrapping to a mobile width stops text running past the edge of a vertical video or hiding behind platform buttons, which is the most common reason repurposed captions look broken.
• Higher retention on muted playback: Most short-form viewing starts with the sound off, so short, high-contrast captions keep people watching past the first seconds.
• Minutes instead of an afternoon: Reformatting a few hundred cues by hand is a long, error-prone job; one run does the whole file and leaves the timings alone.
• Consistent look across a series: Using the same width and uppercase setting for every clip keeps a channel's captions visually uniform without a written style guide.
• No re-syncing afterwards: Because only the text changes, the output drops straight back into your edit without any timing adjustment.
• Client work stays confidential: Since the rewrap runs in your browser, unpublished campaign scripts are never sent to a server.