SRT Editor Online: Edit Subtitles While the Video Plays

Why an SRT is easier to fix with the video beside it

In a text editor an SRT is a column of numbers and timestamps. You can correct spelling there, but you can't tell whether 00:04:12,480 is the moment the speaker starts the sentence, whether a line stays up long enough to read, or whether two subtitles collide. Edit the same file against the video and those questions answer themselves: the playhead shows which line is live, the timeline shows each line as a bar you can stretch, and the editor flags lines that break common reading rules. A plain text editor still has its place for a quick find-and-replace, and editing an SRT in a text editor covers that route.

Open, fix and re-save an SRT

1. Open the editor on this page, switch the AI subtitle option off and choose the video the SRT was made for.
2. Click Import SRT / VTT and pick the file. The notice reports how many subtitles loaded and how many blocks were unreadable.
3. Play the video. Space pauses, Left and Right step a second (hold Shift for a tenth), and Up and Down jump between lines.
4. Click a line's text to correct it, or edit its start and end times in the list to the millisecond.
5. Work through anything marked with a warning.
6. Click Export SRT. The file downloads under the video's name with an .srt extension.

Edits are saved as a draft in this browser as you go, so closing the tab by accident doesn't lose them; reopening the same video brings the draft back.

Which tool fixes which problem

A misheard or misspelt word

Click into the line and type. Undo and redo cover every edit, including the import itself.

A line that appears too early or too late

Drag its bar on the timeline, or drag one edge to change only the start or the end. Times snap to 10 ms.

A subtitle too long to read in time

Put the playhead where the sentence breaks naturally and click Split.

Two fragments that belong together

Select the first and click Merge to join it with the next.

A line nobody wrote

Pause where it should begin and press Enter to add one at the playhead.

Every line out by the same amount

Use "Shift all by" with a positive or negative number of seconds. Shifting subtitle timing explains how to tell a constant offset from drift.

What the exported SRT looks like

Export rebuilds the file from scratch rather than patching the original, which is why it tidies up problems you never touched:

• Subtitles are numbered from 1 in the order they appear, so gaps, duplicates and out-of-order numbers from the original disappear.
• Every timestamp is written as hh:mm:ss,mmm with a comma, even if the source used dots.
• The file is UTF-8 with a byte order mark and Windows-style line breaks, so video editors and platforms don't have to guess the encoding.
• Lines with no text, and lines whose end isn't after their start, are left out.
• Only text and timing are written. Tags such as <i> or <font color> and position codes like {\an8} were stripped on import and don't come back.

Overlapping lines are exported as they are, so clear those warnings first. If the platform you upload to expects a particular name, such as a language code before the extension, rename the download; subtitle file naming lists the common patterns.

Warnings to clear before you export

The list flags lines that will trouble viewers: an end time before the start, a line with no duration or no text, one shown for under 0.8 seconds, an overlap with the neighbouring line, more than three lines of text, a line longer than 42 characters (it wraps on screen), and reading speeds above 21 characters per second for most scripts. Chinese, Japanese, Korean and Thai have their own lower limits. Not every warning must be fixed, since a quick exclamation can be fine, but each deserves a look. The SRT checker page explains what triggers each warning and how to resolve it.

Where this SRT editor stops

• It needs the video. There is no text-only mode; the toolbar appears once a video is loaded.
• It reads SRT and VTT. ASS, SSA and SBV files don't open.
• Per-line italics or colours can't be kept. If a broadcast or festival deliverable requires them, a desktop subtitle editor such as Subtitle Edit or Aegisub is the better fit for that file.
• It doesn't turn the file into another language. Translation here works from the video's speech, through translated subtitles or the editor's AI option.

On a phone or tablet the editing and SRT export work in any modern browser; only rendering a subtitled video needs a computer.

Three editing sessions

For the last case, the file can come from the AI subtitle generator or any other tool; to start a file from nothing instead, see creating an SRT file.

About the subtitle editor on this page

Opens

MP4, MOV, M4V, WebM, MKV videos your browser can decode

Subtitles from

AI (from the speech, optionally translated into one of 21 languages), an SRT or VTT file, or typing them in

You download

An MP4 with the subtitles drawn into the picture at the original resolution and frame rate, plus SRT and VTT files

Cost

Editing, styling, rendering and SRT/VTT export are free, with no account and no watermark. AI subtitles cost 1 credit per minute (5-credit minimum per video); signing in with Google gives 100 free credits and accounts get 10 free credits a day

Privacy

The video never leaves your device and is rendered in your browser. Only for AI subtitles is the audio sent, over HTTPS, and it is deleted within 30 minutes of delivery

Rendering needs

Chrome or Edge 94+, Safari 16.4+, or Firefox 130+ on a computer. Editing and SRT/VTT export work in any current browser