Line Length Checker

The Line Length Checker audits a SubRip file for lines too long to read on screen. Paste the file into the SRT Content box, set Max characters per line, and you get a plain-text report - saveable as a .txt file - naming every offending line by cue number, line number, actual character count and the limit it broke. A clean file returns a single all-clear message instead.

Character-per-line limits exist because a caption must be read in seconds while the picture moves. Most broadcast and streaming specs settle near 42 characters, with house styles at 37 or 40; beyond that text wraps unpredictably or is clipped on a phone. Subtitlers, localisation vendors checking supplier files, accessibility teams working to Section 508 and creators cleaning auto-captions all need the offenders found fast.

The check is per display line, not per cue: each cue's text is split on its existing breaks and every resulting line measured alone, exactly as a viewer sees it. Counting is raw, so spaces and punctuation are included the way a broadcast spec counts them, and if Max characters per line is blank or zero the tool falls back to 42.

This is a read-only audit - your subtitles are never modified - and it runs in the browser with no upload.

• Configurable Max characters per line: Type any limit into the field to match your house style or client spec, and leave it empty to use the default of 42 characters.
• Per-line measurement: Every display line inside a cue is measured separately, so the report reflects what the viewer sees rather than the total length of the cue.
• Precise location in the report: Each finding names the cue number and the line number within that cue, so you can jump straight to the right place in your editor.
• Actual character counts: The report states how many characters the line has and what the limit was, which tells you whether it needs a small trim or a full re-write.
• Clear pass result: When every line is within the limit the tool returns a single confirmation message instead of an empty report, so a clean file is unambiguous.
• Spaces and punctuation counted: Length is measured on the raw line text, matching the way broadcast character-per-line rules are written.
• Non-destructive audit: The subtitle file itself is untouched; the downloadable .txt report is the only output, so it is safe to run at any stage.
• Instant on long files: A full feature-length subtitle track is scanned in the browser with no upload and no waiting.

1. Click Load sample to drop a demonstration subtitle file into the SRT Content box and see the report format.
2. Paste the subtitle file you want to audit into the SRT Content box, keeping its original line breaks intact since those define the display lines.
3. Set Max characters per line to your target - 42 for the usual broadcast maximum, or 37 or 40 if your client specifies a tighter limit.
4. Press Run to generate the report of every line that exceeds the limit.
5. Read the results: each entry gives the cue number, the line within that cue, the measured length and the limit, so you can work down the list in order.
6. Use Download to save the report as a .txt file for your QC records, or Copy to paste it into a ticket for whoever is fixing the file.
7. Fix the offenders - the Subtitle Line Breaker will re-wrap them at word boundaries - then run this check again to confirm the file comes back clean.

Example 1 - a single over-long line at the default limit. With Max characters per line left at 42, one cue carries a 60-character sentence on one line.

Input cue:
7
00:01:12,400 --> 00:01:15,900
I told him this would happen if nobody checked it.

Report:
1 long line(s):
Cue 7 line 1: 50 chars (max 42).

The report tells you where to look and by how much you are over, so you know an eight-character trim or a line break will fix it.

Example 2 - tighter client spec. Setting Max characters per line to 37 for a client house style flags a second line the default would have passed, for instance Cue 12 line 2: 39 chars (max 37). Re-running after re-wrapping returns the all-clear message instead of a list.

• Deliveries that meet the spec: Character-per-line limits are contractual for most broadcasters and platforms, and catching breaches before hand-off avoids a rejected file and a redelivery fee.
• Captions people can actually read: Keeping lines inside a sensible limit gives viewers time to read the whole caption before it cuts, which matters most for fast dialogue.
• Nothing clipped on small screens: Phone and tablet players truncate or shrink over-long lines, and an audit catches that before your audience does.
• Faster QC rounds: Instead of scrolling a thousand cues you get a targeted list of exactly which cue and line to fix, with the numbers to justify the change.
• Evidence for your records: The downloadable .txt report is a simple artefact you can attach to a QC sheet or send back to a supplier.
• Safe with confidential content: The audit runs in your browser, so scripts under embargo can be checked without uploading them anywhere.