SRT Numbering Fixer

The SRT Numbering Fixer takes the subtitle text you paste into the SRT Content box and returns a rebuilt SubRip file in which every cue carries a clean sequential index counting from 1. Gaps, duplicates, out-of-order numbers and missing indices are all resolved in one pass, and the corrected file downloads with a .srt extension.

SubRip expects each block to open with a counter, and although a few forgiving players limp along without one, plenty of the software that matters will not. Strict validators reject the file, some encoders stop reading at the first inconsistency, and translation memory tools can silently mis-segment a file whose numbering jumps. Broken counters appear when two reels are merged, when cues are deleted by hand, when a spreadsheet round trip drops a column, or when someone duplicates a block and forgets to change the number.

Rather than patching numbers in place, the tool parses the whole file into a cue list and writes it out from scratch, emitting indices in strict order. The output is therefore normalised as well as renumbered: blocks are separated by a single blank line and timestamp lines use the standard HH:MM:SS,mmm pattern with a consistent arrow between in and out points. Cue order follows the source file, and times and dialogue are copied through untouched, so only the labelling and layout change.

Because it runs entirely in your browser nothing is uploaded, and a several-thousand-cue file is rebuilt instantly.

• Sequential renumbering from 1: Every cue in the SRT Content box is reissued with a clean counter in order, eliminating gaps, repeats and numbers that restart mid-file.
• Timing and text preserved: Start times, end times and the dialogue itself pass through unchanged, so renumbering can never alter how the subtitles play.
• Whole-file rebuild: The output is regenerated from the parsed cue list instead of being patched, which is why the fix is complete rather than partial.
• Structural normalisation: Blank-line separators between blocks and spacing around the timestamp arrow are written consistently, cleaning up files that have been edited by several people.
• Standard timestamp form: Times are emitted in the conventional HH:MM:SS,mmm SubRip pattern, so the file reads correctly in strict parsers.
• Original order respected: Cues are numbered in the sequence they appear in the source, so the tool never reshuffles your file behind your back.
• No configuration to get wrong: There is a single input box and a run action, which makes this a safe final step in any batch workflow.
• Handles large files locally: Feature-length and series-length subtitle tracks are processed in the browser without upload and without a noticeable wait.

1. Paste the subtitle file with broken numbering into the SRT Content box, or press Load sample to see the effect on a file with deliberately messy indices.
2. Scroll the source briefly to confirm the cues are in the chronological order you want, since the tool numbers them in the order they appear rather than sorting by time.
3. Press Run to rebuild the file; the renumbered SRT appears in the output panel straight away.
4. Check the first cue reads 1 and that the final index matches the number of captions you expected in the file.
5. Compare a couple of timestamp lines against the source to satisfy yourself that only the counters and the spacing have changed.
6. Copy the output or download it as a .srt file, and load it into your player or subtitle editor to confirm it now opens without a parse warning.

Example 1 - gaps left by deleted cues. Two captions were removed by hand and the surviving numbers were never closed up, which some validators treat as a malformed file.

Before:
1
00:00:01,000 --> 00:00:04,000
Good morning, everyone.

4
00:00:05,000 --> 00:00:07,200
Let us start with the numbers.

After:
1
00:00:01,000 --> 00:00:04,000
Good morning, everyone.

2
00:00:05,000 --> 00:00:07,200
Let us start with the numbers.

Example 2 - a merge that restarted the count. Two reels were concatenated, so the counter drops back to 1 partway through and the second half is numbered as a duplicate set.

Before: ... 118, 119, 1, 2, 3 ...
After:  ... 118, 119, 120, 121, 122 ...

In both cases the timings and dialogue are identical afterwards; only the index labels change, which is enough to make a previously rejected file valid.

• Files stop failing validation: Non-sequential indices are a classic automatic reject on ingest, and a one-click renumber removes that failure mode entirely.
• Merged reels behave as one file: After joining episodes or acts, renumbering makes the combined track look like it was authored in a single session.
• Nothing is risked: Since timings and dialogue are copied through untouched, you can run the fixer as a routine last step without reviewing the whole file again.
• Downstream tools cooperate: Encoders, translation memory systems and subtitle editors all read a cleanly numbered, consistently spaced file more reliably than a hand-patched one.
• Saves an entire manual pass: Renumbering hundreds of blocks by hand is exactly the kind of work that introduces new mistakes, and this removes it completely.
• Your captions stay private: The rebuild happens in your browser, so unreleased dialogue is never sent to a server.