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Blocking VTT errors
- Missing or malformed
WEBVTTsignature - Invalid timestamp shape or end before start
- Malformed cue setting values
STYLEorREGIONafter the first cue- Unrecognized document blocks or NUL characters
Local WebVTT editing · Nothing uploaded
Free VTT Subtitle Editor
Fix subtitle text and timing, preview cues against your video, catch
WebVTT errors, and download a faithful .vtt file. No
signup, no watermark, and your subtitle or media never leaves this
browser.
Video preview
VTT-aware validation
Faithful export
Edit a WebVTT subtitle file
Local media
No media loaded
Preview & timeline
Drag a cue or either edge to retime it. Click empty timeline space to move the preview playhead. Waveform decoding depends on browser codec support.
00:00:01.000 → 00:00:04.200
Welcome to the private VTT subtitle editor.
Cues3
Words21
Timeline12.0s
Preserved blocks2
Structured edit
Subtitle cues
Live quality control
VTT validation
Format errors block download. Editorial warnings are optional guidance.
0 errors
1 warnings
Header metadata, STYLE, and NOTE blocks are preserved.
Open Raw VTT to inspect or edit non-cue blocks without losing document order.
Three steps · about five minutes
How to edit a VTT subtitle file online
Start with the file you already have, make exact corrections, and keep WebVTT-only data intact.
-
01
Open or paste the VTT
Choose a
.vttfile, paste WebVTT text, or start blank. Parsing happens locally in this tab. -
02
Edit and preview cues
Fix text, start/end time, cue IDs, and settings. Load local media when you need to check synchronization.
-
03
Validate and download
Resolve format errors, review readability warnings, and download a corrected WebVTT file.
VTT-aware by design
What this editor preserves
Generic subtitle editors often reduce WebVTT to start time, end time, and one line of text. This editor keeps the rest of the document in order—even when a feature is not rendered visually.
See the WebVTT file structure guide →Cue identifiersEditable
line, position, size, align, vertical, regionEditable & preservedPayload line breaks and markup textPreserved
NOTE, STYLE, REGIONPreserved in orderHeader metadata and unknown blocksPreserved & flagged
Know what must be fixed
WebVTT errors vs subtitle quality warnings
A valid VTT can still be hard to read. The editor keeps conformance failures separate from configurable editorial guidance.
i
Editorial warnings
- Overlapping or out-of-order cues
- Reading speed above 20 characters per second
- Lines over 42 characters or more than two lines
- Display duration below 1 second or above 7 seconds
- Empty visible cue text
The warning thresholds are editable house rules, not universal WebVTT requirements. Follow the delivery platform's own style guide when it specifies different limits.
captions.vttWEBVTT
WEBVTT
NOTE Keep this production comment
speaker-alice
00:01.000 --> 00:04.200 position:20% align:start
<v Alice>Welcome to the editor.
This line break is preserved.
WebVTT, not generic text
A cue is more than two timestamps
WebVTT supports optional cue IDs, positioning and alignment settings, multiple payload lines, voice and class spans, comments, styles, and regions. Editing only the visible sentence can silently break layout or production metadata.
The preview intentionally renders a safe plain-text version of cue payloads. It never executes file content as HTML.
Read the current W3C WebVTT specification →
Common VTT repair jobs
One editor for the fixes people actually make
Fix subtitles that are out of sync
Shift every cue by an exact positive or negative millisecond offset, then fine-tune individual edges on the timeline.
Correct or translate cue text
Edit line by line, preserve deliberate breaks, and use find/replace for repeated names, punctuation, or terminology.
Check captions against the video
Load local media, scrub to a cue, and see its safe text overlay without sending the video anywhere.
Find why a platform rejects the VTT
Check the signature, timestamp syntax, timing order, cue settings, and advanced block placement before export.
Questions before you open a file
VTT subtitle editor FAQ
Does this VTT subtitle editor upload my files?
No. VTT parsing, editing, validation, media preview, waveform analysis, and export happen in your browser. Subtitle text, filenames, timestamps, and media are not sent to the site or analytics.
What parts of a WebVTT file are preserved?
The editor preserves the WEBVTT signature and header metadata, cue identifiers, cue settings, payload line breaks and markup text, plus NOTE, STYLE, REGION, and unrecognized blocks in document order.
Can I preview VTT subtitles with a video?
Yes. Load a local video or audio file to play it in the browser and see the active cue. The media is referenced with a temporary browser object URL and is never uploaded.
Can I shift every VTT timestamp at once?
Yes. Enter a positive or negative offset in milliseconds. You can reject negative results or clamp the first cue to zero while preserving relative timing.
What does the VTT validator check?
Blocking checks cover the WEBVTT header, timestamp syntax, start/end order, cue settings, and block placement. Separate editorial warnings cover overlaps, short or long duration, reading speed, line length, line count, and empty cues.
Can I convert the edited VTT to SRT?
Yes, but SRT cannot represent every WebVTT feature. The editor warns that cue settings, styles, regions, comments, metadata, and some payload markup are omitted from SRT.
Will my subtitle draft survive a refresh?
Edits are saved as a local browser draft. On a later visit, the editor asks before restoring it and provides a clear-draft control. Local video or audio is never stored.