Subtitle editor
Give every word its moment. Edit SRT or VTT captions, fix their timing, and see your style on the video. Save subtitles or burn them into the picture.
A caption studio for short clips. Precise timings. Reversible edits.
Open captions, fix their timing, save your finished video.
THE CAPTION STUDIO
Every word. Right on time.
Captions 0
Your story starts here.
Open subtitles, paste a transcript with timings, or add your first cue.
You can edit captions without a video.
Fix subtitle sync
Positive delays captions. Negative brings them earlier.
Give your words a picture.
Add a video to preview timing and burn captions in.
MP4, MOV or WebM supported by your browserAdd captions to see their timing.
Select a caption to edit its text and timing.
All timings keep three decimal places. Your original files stay untouched.
↑ / ↓: 0.1s · Shift: 1s · Alt: 1ms
25 bundled fonts. Selected fonts load from floi. Bold and italic are browser-synthesised.
Style is burned into video. SRT and VTT downloads contain plain text and timing.
Keep captions switchable. Your original video stays unchanged.
Signed in, typed text and settings save automatically to your private account. Text opened from files stays in this browser’s local storage. Files stay in your browser. Account saving
How to edit subtitles online
Open your video and captions
Choose a video and an SRT or VTT file. You can also paste subtitles or start with Add cue.
Fix the words and timing
Select a cue, edit its text and preview its timing. Choose a caption style before burning it into video.
Choose what to download
Save an editable subtitle file, or burn permanent captions into an MP4 or WebM. Your original stays unchanged.
Using the caption studio
Edit the subtitle document first. Load a video when you need to check sync or produce permanent captions.
Your files and caption list
Open one video and one subtitle file together, or drop them into the studio. An invalid subtitle import leaves your existing edits intact.
| Control | What it does |
|---|---|
| Open your files / Choose video | Open a local video, SRT or VTT. Loading a new subtitle document replaces the current captions. |
| Paste subtitles / Import captions | Import timed SRT or WebVTT text. Keep current captions closes the paste window without importing. |
| Try sample captions | Replace the document with three sample cues. Try styles without supplying a file. Undo restores your previous captions. |
| Find a caption / Only issues | Filter by text, or show only cues with timing and reading warnings. |
| Add cue | Add a two-second cue at the preview time. Type its text before exporting. |
| Undo edit / Redo edit | Step through up to 30 document edits. Style controls are separate from this undo history. |
Preview and exact timing
Select a caption to seek to its start. Click the preview caption to select it and bring its row into view. The timeline shows the current 30-second window. Scrubbing changes that window. Select a cue to reveal its edge handles. Drag either handle to extend or shorten it within the visible window. Undo edit restores the previous timing. Focus a handle and use Left or Right for a 0.1-second adjustment. Shift changes the step to one second; Alt changes it to one millisecond. The list shows 100 cues per page; use Previous captions and Next captions to browse. The preview and the exported video use the same caption-drawing code.
Use Play preview, Pause preview and the Preview time slider to check sync. Mute preview silences playback only; exported audio remains included.
Edit cue
Caption text preserves line breaks. Start time and End time use HH:MM:SS.mmm. In either time field, Up increases the time and Down decreases it by 0.1 seconds. Hold Shift for one-second steps or Alt for one-millisecond steps. Start at playhead and End at playhead use the video’s current position.
Split and merge
Split cue uses the playhead inside the cue, otherwise its midpoint. It splits text at your cursor, or near its middle. Merge with next joins text and timing. Delete cue is reversible with Undo edit.
Fix subtitle sync
Enter Shift seconds and choose Shift all. Use 0.5 to delay every cue by half a second. A shift that moves any cue below zero is refused.
Reading warnings
The checks flag overlaps, empty captions, lines above 42 characters, and reading speeds above 20 non-space characters per second. These are review prompts, not an accessibility certification.
A Beyond video warning means a cue ends after your video. Review it before burning captions. Empty captions and invalid timings block export.
Caption style
Text colour and Outline colour accept any colour. Outline width sets the stroke as a percentage of font size. Set it to zero to remove the outline. Box colour and Box opacity control the background. Zero opacity removes the box.
Line spacing adjusts the gap between lines. Italic and Shadow change the text appearance. Reset style restores the defaults. Bold and italic use browser synthesis for fonts with a single bundled weight.
Choose Outline, Yellow or Box as a starting point. Adjust Font, Weight, Position and Alignment. The preview shows the active caption at the current time.
| Setting | Effect |
|---|---|
| Text size | A percentage of the picture’s shorter edge. It scales with the video resolution. |
| Safe margin | Distance from the top or bottom edge as a percentage of picture height. |
| Font | Choose from 25 bundled fonts or three system families. Bundled fonts load from floi when selected. |
| Position | Bottom, Middle or Top. Check that the captions do not cover faces or essential detail. |
Download subtitles or burn captions into video
Open Export and choose Subtitle file for switchable captions, or Captioned video for permanent text. SRT and WebVTT downloads do not include the preview style.
- Subtitle format: download SRT or WebVTT, or use Copy SRT / Copy VTT.
- Video format: MP4 uses H.264; WebM uses VP9. Browser support differs.
- Maximum video edge: choose 1280 px or 1920 px. The aspect ratio stays intact and small videos are not enlarged.
- Burn MP4 / Burn WEBM: encode locally, with progress shown below the controls. Cancel export keeps your edits.
- Focus mode: use Narrow, Wide or Full to size the panel. Done, Escape or browser Back returns to the page.
Keyboard controls
Normal typing remains untouched. These shortcuts work when focus is on the studio rather than a text field.
| Keys | Action |
|---|---|
| Ctrl / ⌘ + Z | Undo a document edit. Add Shift to redo. |
| Space | Play or pause the video. A focused button keeps its normal activation behaviour. |
| ← / → | Move the preview by 0.1 seconds. In the tabs, switch tabs instead. |
| Home / End | In the tabs, focus the first or last tab. |
What this tool will not do
It does not transcribe speech, translate captions or produce word-by-word animations. It does not preserve ASS styling or advanced WebVTT layout.
Subtitle editing accepts up to 10,000 cues and 500,000 source characters. Video input is capped at 500 MB. Burning supports clips up to five minutes, with a maximum 1920-pixel edge.
HDR video is refused during export. Protected videos and unsupported codecs cannot be decoded. Large clips may exhaust a phone’s memory; a desktop editor is a better choice for long films.
Frequently asked questions
How do I edit an SRT file online?
Open your SRT with Open your files, or choose Paste subtitles. Select a caption and edit its text, start time or end time. Choose Download SRT to save your changes. You do not need to load a video for text or timing edits.
Can I add subtitles to a video permanently?
Yes. Open your video and captions, choose a style, then open Export. Select Captioned video and choose MP4 or WebM. Burning makes the text part of the picture. It cannot be switched off or edited in the exported video.
How do I fix subtitles that are out of sync?
Open Fix subtitle sync and enter a shift in seconds. A positive number delays every cue. A negative number makes every cue earlier. Use individual start and end fields when only one caption is wrong. A fixed shift cannot correct timing that drifts progressively.
Can I convert SRT to VTT or VTT to SRT?
Yes. Open either format and choose the other under Subtitle format in the Export tab. Both downloads contain text and millisecond timings. WebVTT layout settings, styling blocks and inline formatting are simplified on import. Keep the original file if you need those features.
Is this subtitle editor free and without a watermark?
Yes. Editing, subtitle downloads and video burning are free, without a watermark or required account. Video export supports clips up to five minutes and 500 MB input. It depends on your browser’s codecs and available memory.
Does burning captions reduce video quality?
The video must be re-encoded to draw captions into its frames. That can change quality and file size. The original aspect ratio is kept. The maximum video edge controls downscaling, without enlarging a smaller source. Audio is copied where possible and otherwise converted to a supported codec. Export stops if a media track cannot be preserved.
Does it generate subtitles automatically?
No. This version edits existing captions or captions you type yourself. Automatic transcription is a separate task. Open the video in audio to text, which writes timed SRT lines, then press Edit as subtitles to bring them here.
Are my video and subtitle files uploaded?
Your files are read and processed in your browser. Video bytes, previews and filenames never enter account saving. Imported captions and later edits stay in this browser’s local storage. Typed or pasted captions, timings and settings save privately when signed in. Signed-out drafts stay on this device. Reopen your video after returning to the tool.
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