SubToolbox

SRT Viewer — Read, Check & Quick-Fix Subtitle Files

Open SRT or VTT and read it as a clean cue table — with one-click fixes for overlaps, numbering, tags and reading speed.

Quick answer: Open a subtitle file to view every cue with its timing, duration and reading speed. The report counts real problems — overlaps, reversed times, text above 21 chars/sec, lines over 42 characters — and each has a one-click fix.

Drop a subtitle file here, or browse — it stays on your device

Core facts
ReadsSRT, VTT, ASS/SSA, SBV, TTML, .sub (auto-detected)
ShowsIndex · start–end · duration · chars/sec · text
ChecksOverlap · inverted timing · empty cue · >21 c/s · >42-char lines
FixesRenumber · fix overlaps · strip tags · remove [sound] labels · drop empty cues
PrivacyRuns in the browser; no upload

What this tool does

Most subtitle problems are invisible until someone presses play. This viewer opens a file the way a player will see it — as an ordered list of cues — and runs the checks broadcast style guides are made of: no two cues may overlap, end must be after start, text should stay under roughly 21 characters per second and 42 characters per line, and empty cues are never useful. Each found issue is listed beside the cue that caused it, and one-click repairs handle the mechanical ones: renumbering, pulling overlaps apart with a minimum gap, stripping stray HTML and {\tags}, removing bracketed sound labels like [ Music ], and dropping empty cues. The repaired file downloads as clean SRT.

Common uses

  • Checking a file from a freelancer or a converter before publishing
  • Finding why captions jump or flash in a player
  • Cleaning auto-generated captions full of tags and sound labels
  • Reading a subtitle file's content without opening a video editor

The checks, in plain words

Overlap: cue A's end is after cue B's start. Inverted: end before start — usually a broken edit. Empty: a cue with no text (players may show a blank flash). Reading speed: over 21 chars/sec, the line outlives its welcome. Long line: over 42 characters, which on two-line displays means the text will wrap unpredictably. Together these five checks cover the majority of “subtitles look broken” reports.

Frequently Asked Questions

Why are overlapping cues a problem?
Players render overlapping cues differently — some stack them, some flash the second on top of the first, some skip it. Broadcast specs simply forbid them; fixing overlaps costs nothing visually and removes a whole class of player quirks.
What does 21 characters per second mean?
Reading-speed ceiling: the cue's character count (spaces excluded) divided by its duration. Above roughly 20–21 c/s, viewers cannot finish the line — the same ceiling used by major platform style guides.
Will the fixes change my timings?
Only where they must: overlap repair nudges the later cue's start to clear the earlier one's end, and inverted cues get a minimum duration. Everything else is left untouched.
Can I edit the text of individual cues here?
This page focuses on viewing and one-click repairs. For building a file cue by cue from scratch, use the SRT file generator.

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