Free forever · Privacy-first

    Free Caption Line Length Checker

    Free line-length checks for caption tracks. Spot cues that will wrap badly on mobile before you burn them in. Drop an SRT or VTT, see which lines overshoot, fix them locally.

    • Looks paidActually free
    • No uploadRuns on your device
    • No accountNothing to sign up for
    • No watermarkYour file, untouched

    More free subtitle tools

    Same quality bar. Still free. Still no upload.

    Part of free TikTok tools, free Instagram tools, free YouTube tools and free LinkedIn tools.

    Your files never leave your device

    Free to use, with no account, no usage limit and no watermark, because the work runs on your device rather than on our servers.

    This is not a promise about how carefully we handle your upload. There is no upload. The file you choose is read into memory by your own browser, processed there, and handed back as a download — the tool has no server component and makes no network request with your data.

    • Nothing is stored. We never receive the file, so there is no copy to retain, no retention period to disclose, and nothing to delete on request.
    • Nothing is transmitted. No upload endpoint, no analytics payload carrying file contents, no third-party processor.
    • You can verify it. Load this page, disconnect from the internet, and use the tool. It still works, because everything it needs is already on your machine.
    • Nothing persists after you close the tab. Files are held in page memory only — not in local storage, not in a cache, not in a database.

    A note on wording, because it matters: we do not describe these tools as “encrypted.” Encryption protects data that travels to somebody else's computer. Your file does not travel, so there is nothing to encrypt and nothing to intercept — which is a stronger guarantee than encryption, not a weaker one. The page itself is served over HTTPS like the rest of the site.

    This makes the tools safe for material you are contractually barred from uploading to third-party services — client footage under NDA, unreleased campaign assets, anything covered by a confidentiality clause.

    How it works

    1. 1. Drop SRT or VTT

      Open the track you plan to burn or upload.

    2. 2. Scan line lengths

      Cues that exceed a readable width are flagged.

    3. 3. Fix and re-export

      Shorten or split long lines, then burn with confidence.

    Questions

    Why check caption line length?

    Long cues wrap into three-plus lines on a phone and cover the face or product. Catching them before burn-in saves a wasted export.

    Does this change my file automatically?

    No. It reports problems. You edit the wording or split cues, then export again.

    Is the track uploaded?

    No. Length checks run locally on the text.

    Related tools

    Stay in the same job cluster. Free tools stay on-device; paid tools are labelled as such.

    These rearrange files. Versely makes new ones.

    Everything on this page works on a file you already have, which is why it costs nothing. Generating something that did not exist (video from a prompt, a voice, a score) runs a model, and that costs credits.