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Caption line length checker
Find lines that are too long for vertical short-form video before you burn in subtitles.
Safe line length reference
For 1080×1920 captions, teams often keep 32–42 characters per line in Latin scripts. CJK lines may use fewer glyphs because each character reads wider. Adjust the limit to match your font size and platform safe margins.
How to use
- Paste caption or subtitle lines (one or many lines).
- Set your max characters per line (default 42 for vertical video).
- Click Check lines and fix any lines flagged over the limit.
Frequently asked questions
- How many characters per line for TikTok or Reels?
- Many editors target 32–42 Latin characters per line on 9:16 video so text does not cover faces or safe zones. Increase the limit if you use larger fonts.
- Does this tool edit my video?
- No. It only analyzes pasted caption text and reports line lengths.
- How is line length counted?
- Each line break starts a new line. Character count uses Unicode code points (emoji count as multiple code units in some fonts—treat results as guidance).
- Can I check an entire SRT file?
- Paste dialogue lines or export text from our SRT to text tool, then run the checker here.
- Why do platforms care about line length?
- Long lines wrap into tall blocks that block visuals and reduce retention on short-form feeds.