Change Subtitle Timing Line by Line

Is it one line or all of them?

Timing problems come in two shapes, and they need different fixes. If every subtitle is early or late by the same amount, that's an offset, and one number fixes the whole file: type it into "Shift all by" in the toolbar, or see shifting subtitle timing for the full method. This page is about the other shape, where most lines are fine but some appear before anyone speaks, linger after the speaker has stopped, flash past too quickly, or step on the next line.

Individual errors like these come from transcripts timed against a slightly different edit, from translated subtitles whose timing was spread by text length, or from someone typing times by hand. They need a person to watch and adjust.

What to have ready

• The exact cut of the video you'll publish. Subtitles timed against a rough cut will be wrong wherever a shot was trimmed.
• The subtitles, as an SRT or VTT file to import, or as AI subtitles generated in the editor.
• Headphones, if possible. The start of a word is much easier to hear than to guess from lip movement.

Retiming a line, step by step

1. Open the editor, choose the video and import the subtitle file, or let AI write the subtitles.
2. Select the line that's off by clicking its row or its block on the timeline, or by pressing Up and Down. The video jumps to the line's current start.
3. Press Left to go back a second, then play at 0.75× or 0.5× from the playback speed menu. Pause where the speech really begins, using Shift with Left or Right to step a tenth of a second at a time.
4. Read the time under the video and type it into the line's start field, or drag the block's left edge to the playhead on the timeline.
5. Play on to where the sentence ends, pause, and set the end the same way.
6. Check the duration shown in the row and any warnings beneath it, then play the stretch once more at normal speed to confirm it feels right.

After a change the list re-sorts by start time, so a line you move past its neighbour will jump to its new place in the list.

Three ways to move a time

Drag an edge

Grab the left or right edge of a block on the timeline to change only its start or only its end. Edits snap to 10 ms, and a line can't be dragged shorter than a tenth of a second.

Drag the whole block

Grab the middle of a block to slide it earlier or later while keeping its length. Handy when the text is correct and the duration is fine but the line is simply late.

Type a time

Click a start or end field and enter a time. It accepts 1:02.345, 62.345 or 0:01:02,345, and a comma or a point before the milliseconds. Press Enter to apply or Escape to cancel; an entry the editor can't read is marked invalid and nothing changes.

For close work, zoom the timeline in until a single second spans a good width on screen. The Fit button zooms back out to show the whole video. Every drag is a single undo step, so Ctrl+Z or Cmd+Z takes back a bad pull in one go.

Reading the timing warnings

Several of the warnings under each row are about timing, and each points to a specific fix.

• Shown for under 0.8 s. A line this short is gone before most people finish reading. Extend its end into any gap that follows, or merge it with the next line.
• Too fast to read. The row shows how many characters per second the line asks of the viewer, with spaces left out of the count, and the target: 21 for Latin and most other scripts, 17 for Thai, 12 for Korean, 9 for Chinese and 8 for Japanese. Give the line more time, trim the wording, or split it at a natural pause.
• Overlaps the previous or next subtitle. Both lines are flagged. During the overlap they're shown stacked together, earlier one on top, which is right for two people talking at once but usually a mistake otherwise. Pull one edge back.
• End before start, or no duration. Usually a typo in a time field. These lines are left out of exports and renders until you fix them.

Text problems such as lines over 42 characters or more than three lines show in the same place. When a line is too long to hold for a readable time, split and merge subtitles explains how Split divides both the text and the time.

Habits that make timing feel right

These are long-standing subtitling conventions rather than rules the editor enforces:

• Start the line when the voice starts. A subtitle that arrives a beat late feels much worse than one that's a fraction early.
• Let the line stay a moment after speech ends, so slower readers can finish, but don't carry it into the next speaker's turn.
• Leave a short gap between consecutive lines. When one subtitle replaces another with no gap, the eye can miss that anything changed.
• Avoid holding a line across a hard cut where you can. Text that hangs over a new shot draws attention to itself.

Subtitle timing guidelines goes deeper into durations, gaps and shot changes.

When a line won't cooperate

• It stops at the start or end of the video. Lines can't be dragged before 0:00 or past the video's last moment.
• The whole file drifts further out as it plays. That's usually a frame-rate mismatch, for example subtitles made for a 25 fps release played against a 23.976 fps one. The editor has no stretch or two-point sync, so either retime the drifting lines here or correct the drift first in a desktop tool such as Subtitle Edit, then import the result. Syncing subtitles with video compares the approaches.
• Sound and picture are out of step with each other. No amount of subtitle timing fixes that; see audio and video out of sync first.
• AI subtitles feel choppy. They come as short one-line captions of up to about 2.6 seconds, each starting on the first spoken word, so a sentence may span several lines. Translated AI subtitles are split by text length, so their per-line timing is approximate and worth a careful pass. Fixing auto-generated subtitles suggests a review order.

After the timing is right

Export SRT or VTT to keep the retimed file, or render the video so the timing is fixed into the picture. If you haven't generated subtitles yet and want a timed file to start from, the AI subtitle generator produces one you can bring back here for fine-tuning.

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