Free tool

Fix a subtitle file without uploading it

Convert between SRT and WebVTT, shift every cue when the captions run ahead of the sound, and re-wrap lines that are too long to read on a phone. It all happens in this page: the file is read by your browser and never leaves it.

Paste a subtitle file above, or open one.

Read and rewritten in this page - nothing is sent anywhere.

SRT and VTT, and when each one is wanted

They are the same idea written two ways: a list of lines, each with a start and an end.

FormatWhere it is asked for
SRT The one almost every platform and editor accepts for upload. Numbered cues, commas in the timestamps.
WebVTT The web standard, used by video players on a page. Same timings with full stops, and a WEBVTT line at the top.

If something rejected your file, the usual cause is one of three things: the wrong one of these two formats, a missing blank line between cues, or a timestamp written without hours. Passing the file through here rewrites all three correctly.

When the captions are out of step

If the words appear consistently early or consistently late, the whole file is offset and a single shift fixes it: play the video, note by how much the first line is out, and put that number in - negative to pull the captions earlier, positive to push them later.

If the gap grows as the video goes on, a shift will not help. That is a different fault - the transcript was made against a different edit of the video, or against a version at another frame rate - and it needs re-timing rather than moving.

Lines that are too long to read

A caption file made for a desktop player often carries lines of seventy or eighty characters. On a phone that either shrinks to nothing or wraps into four lines that cover the picture. Around forty characters a line is the width that stays readable at arm's length, which is where most short-video captions sit.

Burned-in captions are a different job again, and a better one for short video: most of it is watched with the sound off and with no caption track switched on, so the words have to be part of the picture. Caption styles covers what those look like, and why a short gets no views covers where a silent, caption-less clip loses its audience.

SnapDub writes the captions itself as it cuts - transcribed, timed, wrapped and burned into the clip in the style you pick - so for clips made there this tool is for the files you already have from somewhere else.

Captions without the file

Let the clips come out already captioned

Start free with 500 credits a month - no card required.

Start clipping free
About this tool

Questions about subtitle files

Is my subtitle file uploaded anywhere?

No. It is read by your own browser and rewritten in the page. Nothing is sent to us or stored, and there is no account.

What is the difference between SRT and VTT?

The same cues written two ways. SRT numbers each cue and uses a comma before the milliseconds; WebVTT uses a full stop and opens with a WEBVTT line. Upload forms usually want SRT, web players usually want VTT.

How do I fix subtitles that are out of sync?

If they are out by the same amount all the way through, shift every cue by that number of seconds - negative to make them appear earlier. If the error grows over time, the file was timed against a different version of the video and shifting will not fix it.

How long should a caption line be?

Around forty characters for anything watched on a phone. Longer lines either shrink below reading size or wrap into several lines that cover the picture.

Can I upload an SRT to TikTok or Instagram?

TikTok and YouTube both accept a caption file on upload. Instagram does not work that way, which is one reason short video is usually captioned by burning the words into the picture instead.

Does this change the wording or translate anything?

No. It only converts the format, moves the timings and re-wraps the lines. The words come out exactly as they went in.