Shift Subtitle Timing by a Fixed Amount

Offset or drift: the two-point test

Before changing anything, compare the subtitles with the speech at two places far apart: one line in the first minute and one near the end. How the gap behaves between those two readings tells you which problem you have.

Same gap at both points

A constant offset. Something added or removed a fixed stretch of time before the first line, such as a trimmed intro or a logo sting. One shift fixes the entire file.

Gap grows steadily

Drift. The file was timed against a copy that plays at a slightly different speed, so the error builds with every minute. A shift can make one part right, never all of it.

Right until one moment, then off by a fixed amount

A cut difference. A scene, an ad break or a sponsor segment exists in one version and not the other. The lines on each side of the cut need their own correction.

Gap wanders up and down

The timing was rough to begin with, line by line. That is a job for retiming individual lines rather than a global shift.

Most files that arrive "a bit out" belong to the first row.

Measuring the gap precisely

Guessing an offset by eye usually leaves you a quarter of a second off, which viewers notice. Measure instead:

• Select the first spoken line in the list, or press Up and Down until it is selected. The playhead jumps to where the subtitle currently starts.
• Press Left to go back a second, slow playback to 0.5× in the speed menu, and play. Pause on the first syllable of the speech, then use Shift with Left or Right to step a tenth of a second at a time until you land on it.
• Read the time under the preview, which shows milliseconds, and compare it with the line's start time in the list.

The sign is the part people get backwards. If the subtitle shows up before anyone speaks, it needs to move later, so the number is positive. If the speech comes first and the subtitle lags behind, it needs to move earlier, so the number is negative. Take the same reading near the end of the video; if both give the same figure within a tenth of a second or so, you have a clean offset.

In VLC, the G and H keys nudge subtitle delay during playback and show the running total. A player's delay only affects that computer, so apply the same amount here to make it permanent.

Shifting every line in the editor

1. Open the editor on this page and switch off "Write the subtitles automatically with AI" before choosing a video. It is on by default and would start transcribing and ask you to sign in.
2. Choose the video the subtitles belong to: MP4, MOV, M4V, WebM or MKV. A subtitle file can't be opened without one.
3. Click Import SRT / VTT and pick the file. The notice reports how many subtitles came in and how many blocks were skipped.
4. Measure the gap at the start and near the end as described above.
5. Find "Shift all by" at the end of the toolbar. It already holds 0.5, so replace that with your figure in seconds, for example 1.25 or -2.4. A decimal comma such as -2,4 is accepted as well.
6. Click Apply. Every start and end time moves by that amount in one step.
7. Play both checkpoints again. If they are still slightly out, apply the small remainder; shifts add up, so 2 followed by 0.15 equals a single shift of 2.15.
8. Click Export SRT or Export VTT to save the corrected file, or render the video if you want the subtitles burned into the picture.

What the shift does, and doesn't do, to your lines

• Every line keeps its length exactly. Only the position in time changes, rounded to the nearest millisecond.
• A line pushed earlier than 0:00 stops at 0:00 and keeps its length. If several opening lines are pushed past the start, they all begin at 0:00 and pile on top of each other; the overlap warning flags them, and often they are opening credits that can be deleted.
• Nothing stops lines moving past the end of the video. After a large positive shift, check that the last subtitle still starts before the video finishes, because one that starts later is never seen.
• Each Apply is a single undo step. If you typed the wrong sign, Ctrl+Z or Cmd+Z puts every line back where it was.

When the gap keeps growing

Drift almost always comes from playback speed. Films released for 25 frames-per-second television often run slightly faster than the 23.976 frames-per-second version of the same film, so subtitles timed for one slip by roughly two and a half seconds every minute against the other. A gentler mismatch, 29.97 against 30 frames per second, adds only a few seconds per hour and can pass for an offset in a short clip, which is exactly why the second measurement near the end matters. How frame rate works explains the numbers behind this.

The editor has no stretch, frame-rate conversion or two-point sync, and a constant shift leaves a drifting file right in the middle and wrong at both ends. For real drift, a desktop tool such as Subtitle Edit can convert the frame rate or sync the file from two known lines; then import the result here to check it against the picture. For a clip of a few minutes, it can be quicker to shift so the middle is right and drag the remaining stragglers into place by hand. Syncing subtitles with video compares the wider set of approaches.

One look-alike problem has nothing to do with the subtitles. If the voices themselves don't match the lips, the audio track is out of step with the picture, and no subtitle timing can fix that; audio and video out of sync covers it.

When only part of the file is off

"Shift all by" always moves every line; there is no option to shift from a chosen point onwards. When an extra segment sits in the middle of one version, shift the whole file by the amount that suits the longer stretch, then correct the shorter stretch line by line. Dragging the middle of a block on the timeline slides it while keeping its length. If the inserted segment is long and the stretch after it is full of dialogue, it may be faster to split the source file in a text editor, fix each half separately and stitch them back together.

Two offsets and how each was fixed

Keeping the corrected file

The exported SRT is numbered from 1 in time order, uses comma timestamps and is written as UTF-8 with a byte order mark, which keeps accents and non-Latin scripts intact. Lines with no text or no duration are left out. The download is named after your video, so rename it if a platform expects a language code in the file name. To put the corrected file on YouTube, uploading subtitles to YouTube walks through Studio; to burn it into the picture, SRT to MP4 covers the render. If the timing turns out to be beyond repair, the AI subtitle generator times fresh subtitles from the speech itself, at 1 credit per minute of video, and the SRT editor page covers the wider clean-up of a file you already have.

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