Subtitle Splitter

Choose a split method

Use Split by to select one of the five available methods:

• Time ranges - enter one start-end range per line. A cue is assigned by its start time, so a cue that crosses a boundary stays with the range containing its start.
• Cue ranges - enter 1-based, inclusive cue-number ranges such as 1-50.
• Maximum cue count - set the maximum number of cues in each consecutive output.
• File-size target - enter a target in KB. Grouping is an estimate, so a single large cue can exceed the target and the final size can vary with styling, metadata, cue settings, and output format.
• Chapter markers - enter one timestamp per line, followed by an optional title. Markers are sorted and used as boundaries; the timeline also starts at 00:00:00.

Split a subtitle file

1. Drop an SRT or WebVTT file into the tool, or select browse files.
2. Choose a value for Split by and complete its fields.
3. Set Output format, Output timestamps, and Styling (inline markup).
4. When the settings are complete, the computed segments and output files appear automatically.
5. Download each result or choose Download all as ZIP.

After a valid file loads, complete the selected settings and the tool computes the segments automatically. For Chapter markers, markers at the same timestamp are deduplicated, a marker at 00:00:00 does not add another segment, and marker segments with no cues are omitted. If the first positive marker is later than the start, the tool can create an initial Intro segment.

Time ranges and boundary rules

• Enter HH:MM:SS, HH:MM:SS.mmm, MM:SS, or plain seconds in each Time ranges value.
• Ranges are sorted automatically. They may leave gaps, but overlapping ranges are rejected.
• Cues are selected by start time. A cue crossing a boundary stays with the range containing its start.

What the output preserves or changes

• Output cues are renumbered sequentially from 1; original SRT or WebVTT cue identifiers are not preserved. Cue order and text lines are retained unless you choose Strip all inline markup tags.
• Absolute (unchanged from source) keeps the source timeline. Relative (each segment starts near 00:00:00) shifts the first cue in each non-empty segment to exactly 00:00:00.000, based on that cue's start time rather than the requested boundary.
• File-size target uses an estimate based on the selected output serializer, so resulting sizes are approximate.
• Chapter markers are sorted automatically, and markers at duplicate timestamps are deduplicated. The first segment can receive an automatically labelled Intro when appropriate.
• Keep supported tags leaves inline markup unchanged. Strip all inline markup tags removes text matching the tool's generic tag pattern; it does not validate a defined list of supported tags.
• When WebVTT is converted to SRT, WebVTT cue settings are dropped. WebVTT header blocks are copied only to the first WebVTT output.

Troubleshooting split errors

Malformed timestamps, impossible minute or second values, and cues whose end time precedes their start time cause parsing errors. Timestamp components are validated before cues are accepted.

With Time ranges, cues whose start time is outside every entered range are omitted, including cues in gaps between non-overlapping ranges. A cue crossing a boundary is assigned according to its start time.

File-size target is an estimate made before output serialization. A single cue can exceed the requested target, and the actual size can change with preserved or stripped markup, WebVTT metadata, cue settings, and output format.

The tool can reject an empty file, a file with no cues, malformed subtitle blocks, malformed timestamps, cues whose end precedes their start, or invalid numeric values. It also reports invalid or overlapping time ranges, invalid cue ranges, missing or malformed chapter markers, and split settings where no cues match.

For Chapter markers, enter one marker per line. A line contains a timestamp and may include a title; lines beginning with # are ignored, and markers are sorted before segments are built. If the first marker is after the start of the subtitle timeline, the tool may add an automatically labelled Intro segment.

Empty computed segments are omitted. Cue ranges outside the available cues may be limited to the available range, and empty ranges may disappear from the preview. An error appears if no cues remain in any computed segment. The implementation does not define a numeric maximum file size, cue count, or number of output segments.

Processing and limitations

Processing happens in the browser. The implementation has no upload or network-processing workflow. File-size targets are approximate, time ranges cannot overlap although gaps are allowed, and the styling control does not define or validate a supported-tag list. Subtitle timestamps must use valid minute and second components.

Subtitle Splitter FAQ