Subtitle FPS Converter

How to retime subtitles for a frame-rate change

1. Paste content into Paste subtitle content below, or drop/upload a file:, use Drop a subtitle file here, or click browse files. The file control accepts .srt, .vtt, and .txt.
2. Choose Source FPS (frame rate subtitles were timed for). The preset list includes 23.976, 24, 25, 29.97, 30, 48, 50, 59.94, and 60.
3. Choose Target FPS (frame rate of the video now). Select Custom... when the needed value is absent, then enter a number greater than 0 in the matching custom field.
4. Review Before & after preview. Each row shows the cue number, original timing, retimed timing, flags, and text.
5. Click Download to save retimed.srt or retimed.vtt. Click Clear to remove the input and hide the result.

Convert subtitle frame rate with a ratio

Each cue's start and end time is multiplied by Source FPS / Target FPS. With 23.976 as the source and 25 as the target, a cue at one minute moves to 57.542 seconds.

Source FPS: 23.976
Target FPS: 25
Original timing: 00:01:00,000
Retimed timing:  00:00:57,542

The same ratio is applied at every point on the timeline. A fixed-offset change belongs in Subtitle Timestamp Shifter when every cue needs the same time adjustment.

What SRT and WebVTT input accepts

A filename ending in .srt selects SRT parsing. A filename ending in .vtt selects WebVTT parsing. Other uploaded files and pasted text use WebVTT parsing only when the content starts with WEBVTT; otherwise the page uses SRT parsing. SRT timing uses HH:MM:SS,mmm. WebVTT timing uses HH:MM:SS.mmm, with hours optional, and the file must start with WEBVTT.

Empty input, malformed timing lines, missing cue text, and an end time before the start produce an error. The timestamp pattern checks the number of digits, but the code does not separately validate minute or second ranges.

What the retimed subtitle file preserves

• Cue text, order, and count stay unchanged.
• Every exported timestamp is rounded to the nearest millisecond.
• SRT indexes are rebuilt in sequential order.
• WebVTT identifiers and cue settings are retained.
• WebVTT NOTE, STYLE, and REGION blocks are skipped and not exported.

The preview flags a cue when its retimed time overlaps the previous or next cue. Input timestamps use non-negative syntax, and custom FPS values must be greater than zero.

Two subtitle FPS conversion examples

For an SRT file timed at 23.976 fps and a video at 25 fps, choose those values, inspect the changed timings, and download the retimed SRT.

For a WebVTT file timed at 29.97 fps and a video at 30 fps, the preview shows the rescaled cue times and any overlap flags before you save the VTT.

When to use a different subtitle edit tool

Use Subtitle Edit Tools for other direct subtitle-file changes. Use Subtitle Timestamp Shifter for a fixed offset or a linear start-to-end drift. Use Subtitle Style Editor for font, color, outline, alignment, margins, or positioning. Subtitle FPS Converter changes timing by an FPS ratio and leaves styling and video frames alone.

The page reads uploaded files with FileReader. Parsing, previewing, and serialization run in the browser, and this workflow has no request that sends the subtitle content elsewhere.

Frequently asked questions