Free Subtitle Editor & Converter

Who this subtitle workspace helps

Video editors, teachers, podcasters and small business owners often receive a caption file that is almost right. The words are fine, but every line appears a second too early, a few cues overlap, or a client needs WebVTT for a web player while the file arrived as SRT. This editor is built for that cleanup stage.

A common case is a caption file exported from one cut of a video and reused on a slightly different cut. Another is a file timed for a 25 fps broadcast master that drifts further out of sync on a 23.976 fps web version. The global shift and time scale fields handle both without retyping a single timestamp.

It also suits accessibility reviews. The built-in checks point to cues that flash by in under a second, lines longer than 42 characters and cues that ask viewers to read more than 20 characters per second.

Worked example: fixing a late file and a frame-rate drift

Load the example file. Its first cue runs from 00:00:01,000 to 00:00:04,000 and its second from 00:00:05,000 to 00:00:08,000. Suppose speech in your video starts 1.5 seconds later. Enter 1.5 in Shift all cues, leave Time scale at 100 and choose Apply timing adjustment. Exported as WebVTT, the cues now read 00:00:02.500 --> 00:00:05.500 and 00:00:06.500 --> 00:00:09.500.

Now take the original file and assume it was timed for 25 fps but the new video runs at 23.976 fps. The scale is 25 divided by 23.976 times 100, which is about 104.27. With a shift of 0 and a scale of 104.27, the SRT export reads 00:00:01,043 --> 00:00:04,171 and 00:00:05,214 --> 00:00:08,342. Each time is multiplied by 1.0427 and rounded to the nearest millisecond.

If you apply both changes in one step, the scale is applied first and the shift is added afterward.

How the checks and conversions work

SRT writes times as HH:MM:SS,mmm with a comma and numbers each cue. WebVTT starts with a WEBVTT header, uses a period before the milliseconds and does not need cue numbers. On export the tool writes the format you choose, renumbers SRT cues in their current order and keeps the caption text as plain lines.

The reading-speed check removes spaces and divides the remaining characters by the cue duration. A 1.5 second cue holding 60 non-space characters scores 40 characters per second, well over the 20 limit. The overlap check compares each cue with the one listed before it, so use Sort by start time before trusting that finding.

Imports are limited to 2 MB and 5,000 cues. An optional preview video can be up to 100 MB, and it is only used for playback in the page.

Common mistakes to avoid

Pressing Apply timing adjustment twice applies the shift twice, because each run works on the current cues. If timing goes wrong, use Restore imported cues and start again rather than trying to undo by hand.

Do not convert WebVTT files that rely on positioning or styling and expect those settings to survive. The tool tells you when such data was ignored. Also remember that Wrap lines splits text at the width you set, so review line breaks in names and numbers before export.