Online Tool Store
Subtitle Editor
Open an SRT or VTT file, fix the wording and timings against your own video, shift every cue at once, and export it back out. Runs in your browser.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
.srt or .vtt — nothing is uploaded.
Plays locally so you can check timings.
Seconds — decimals allowed. Shifting keeps every cue's duration unchanged.
Cues
How it works
- Load an .srt or .vtt file — or start from the sample cues already loaded.
- Optionally add your video, and the current cue appears over it as it plays.
- Edit the wording and the in/out times, add or delete cues, or shift the whole file at once.
- Export back to SRT or VTT when it reads correctly.
How a subtitle file is actually structured
Both formats are plain text: a list of cues, each with a start time, an end time, and the lines to show between them. Blank lines separate the cues.
SRT 2
00:00:03,500 --> 00:00:07,200
Today we're fixing the hinge
VTT 00:00:03.500 --> 00:00:07.200
Today we're fixing the hinge
The differences are small but they break naive parsers: SRT numbers each cue and separates milliseconds with a
comma, VTT has no numbers, uses a dot, and may add positioning settings after the end time. This editor finds the
timing line by looking for the arrow rather than assuming a fixed line order, so it reads both — and it accepts
shorthand like 01:30,000 without an hours field.
Why a constant offset is the usual bug
When subtitles are out of sync, the fault is nearly always a single fixed offset rather than accumulating drift:
new start = old start + offset
new end = old end + offset // duration unchanged
That happens because the file was timed against a slightly different cut of the video — a longer distributor logo, an added sponsor card, a trimmed cold open. Since every cue is wrong by the same amount, shifting the whole file fixes it in one action. Genuine drift, where subtitles get progressively further out, means a frame rate mismatch instead and needs the times scaled rather than shifted.
The characters-per-second reading under each cue is the other thing worth watching. Subtitling practice puts the comfortable ceiling around 17–20 characters per second; above that a viewer physically cannot finish the line, and the fix is fewer words rather than a longer cue.
FAQ
Are my subtitles or video uploaded?
No. The subtitle file is read as text in your browser and the video plays from your own disk, so neither is uploaded. That matters for unreleased footage and for transcripts of private recordings.
What is the difference between SRT and VTT?
They are nearly the same format with two differences that matter: VTT starts with a WEBVITT header and separates seconds from milliseconds with a dot, while SRT uses a comma and numbers each cue. VTT is what HTML video wants; SRT is what most players and editors expect. You can load either here and export either.
My subtitles are consistently late. What do I fix?
Use the shift control rather than editing every cue. A constant offset usually means the subtitle file was made against a version of the video with a different intro length, so moving every cue by the same amount fixes the whole file at once. Both ends of each cue move together, so durations are preserved.
What do the warnings mean?
They flag the problems that make subtitles behave oddly rather than fail outright: a cue ending before it starts will never appear, overlapping cues get stacked on top of each other by most players, cues under half a second are gone before they can be read, and out-of-order cues break some stricter players.
What is the characters-per-second figure for?
It is the standard readability check in subtitling. Much above roughly 17–20 characters per second, most viewers cannot finish reading before the cue disappears — so if that number is high, the fix is usually to split the cue or trim the wording rather than to hold it longer.
Can it transcribe the audio for me?
No. This edits subtitles you already have — generating them from speech needs a speech recognition model, which is a different tool entirely. Start from an existing file, or from an automatic transcript exported by your video platform.
How we compare
| Feature | Online Tool Store | Upload-based subtitle sites | Aegisub / desktop tools |
|---|---|---|---|
| Subtitles and video stay on your device | ✓ | ✗ | ✓ |
| Preview cues over your own video | ✓ | Sometimes | ✓ |
| Flags overlaps and unreadable cues | ✓ | ✗ | ✓ |
| Reads and writes both SRT and VTT | ✓ | ✓ | ✓ |
| Waveform view for frame-accurate timing | ✗ | ✗ | ✓ |
| Generates subtitles from speech | ✗ | ✓ | With a plugin |
Right for the common jobs: fixing a typo in a caption, nudging a file that runs a second late, or converting between SRT and VTT — all without uploading footage that has not been released. It has no waveform and no speech recognition; for precision timing from scratch, a desktop subtitle editor is the better tool.