SRT Subtitle Tool

📖 Tool Introduction

SRT Subtitle Tool is a free online utility for subtitle makers and video fans. SRT files exported from fan subtitling groups, automatic speech recognition, or translation platforms often suffer from a shifted timeline (for example the video runs 2.3 seconds faster than the subtitles), broken numbering, or a handful of mistyped timecodes. This tool parses and processes everything locally in your browser: it splits the file into cues according to the standard SRT block format (sequence number line, timecode line, text lines, blank line separator) and lists each cue with its start, end and text. You type a shift in seconds (decimals and negatives allowed) and one click moves the whole track earlier or later; timecodes that would fall before zero are clamped to 00:00:00,000. You can also renumber a broken sequence back to 1, 2, 3, and run a format check that validates every timecode, flags cues whose end precedes their start, and reports empty text lines, with a summary count of problems. The preview updates after every operation, a stats line shows the cue count, the first start, the last end and the total duration, and the corrected file downloads as a new .srt. All computation is local, so subtitle text never leaves the browser, which makes the tool safe for film, course and meeting transcripts. Because parsing is fully offline, the tool also works on locked-down machines and slow connections, and it never throttles on large subtitle files. Whether you resync a fan-sub release, align an auto-generated transcript, or repair a corrupted cue numbering, the whole fix-and-download loop takes seconds. A built-in sample loads a short three-cue track the moment you click the example button, so first-time visitors can immediately type a negative shift, renumber and validate without preparing their own subtitle file. Because the parser follows the standard SRT block layout, multi-line cue text and CRLF line endings are handled gracefully, and the exporter re-emits each cue in the canonical one-cue-per-block shape most players expect. The validation report is meant to be read before you ship the file: if a cue ends before it starts, the report lists its index so you can jump straight to the broken line rather than scanning hundreds of cues by eye. The whole workflow needs no account, no upload and no installation, which makes the tool safe for transcripts that carry dialogue from internal meetings, paid course footage or unreleased film screeners.

✨ Key Features

• Timeline shift: enter seconds (negative allowed) to move the whole track
• Auto clamp: timecodes before zero are clamped to 00:00:00,000
• Renumber: reset broken indices to a continuous 1..N sequence
• Validate: checks timecode syntax, end-before-start and empty text
• Live preview: every cue's start, end and text is visible
• Local and safe: subtitles stay in the browser, never upload

📝 How to Use

1. Drop an .srt file into the dashed box, or paste the text into the box
2. Enter the shift in seconds and click Apply shift
3. Click Renumber if the cue indices are out of order
4. Click Validate to check the report for structural problems
5. Click Download SRT to save the corrected file

⚠️ Notes

• Negative shift: a negative value pulls subtitles earlier to fix AV sync
• Zero clamp: timecodes before zero are clamped, no negative times appear
• Validation scope: checks structure and timing only, never translates or edits text
• Encoding: files are read as UTF-8; convert other encodings first
• Offline: subtitles never leave the browser, works on locked-down networks