Timeline scale
Mistake: Entering 0.5 when you mean 50%.
Fix: Enter 50 for 50%; 0.5 represents 0.5%.
Text · Free
Subtitle timeline transformer
Shift and scale an entire subtitle timeline without changing its text.
01Enter your values
Runs in your browserRuns offline in your browser. Once the page and required files have loaded, processing needs no internet.
02Subtitle timeline transformer
Runs in your browser
How it works
Shift and scale an entire subtitle timeline without changing its text.
t′ = round(t × Timeline scale / 100 + Offset × 1000) [ms]
Runs in your browser
Discovery source
Your data stays yours
Inputs are processed on this page and are never sent to a server.
About this tool
Use tool ↑Shift and scale an entire subtitle timeline without changing its text.
New time = old time × scale / 100 + offset. Apply scaling first and offset second; round to milliseconds. Reject negative times and collapsed cues instead of silently clipping them.
How to use it
- Enter your values
Subtitle text · Offset · Timeline scale
- Calculate / generate
Shift and scale an entire subtitle timeline without changing its text.
- Result
1 00:00:02,000 --> 00:00:04,000 12345 2 00:00:05,000 --> 00:00:07,000 67890
Calculation method
- New time = old time × scale / 100 + offset.
- Apply scaling first and offset second; round to milliseconds.
- Reject negative times and collapsed cues instead of silently clipping them.
t′ = round(t × Timeline scale / 100 + Offset × 1000) [ms]
Subtitle timeline transformer
- Subtitle text
- 1 00:00:01,000 --> 00:00:03,000 12345 2 00:00:04,000 --> 00:00:06,000 67890
- Offset
- 1 s
- Timeline scale
- 100 %
Result
1 00:00:02,000 --> 00:00:04,000 12345 2 00:00:05,000 --> 00:00:07,000 67890
Frequently asked questions
Scope and common mistakes
Paste plain-text SRT or WebVTT, up to 100,000 characters. Markup, entities, positioning, STYLE, REGION and NOTE blocks are rejected, not silently removed. Cue starts must be ordered; overlaps are allowed. This is not transcription or a media player. For no speed change use 100%, not 1%; positive offset delays subtitles. A linear transform cannot repair edits or irregular drift. Readability thresholds are your policy, not an accessibility certificate.
Where does my data go?
Calculations run on your device. Form inputs are not sent to a server.
Terms and definitions
Enter your values
- Subtitle text
Enter the source text; it is processed locally.
- Offset
New time = old time × scale / 100 + offset.
Enter a numerical value for this quantity. Use the unit shown beside this field. s
Minimum: -100000000 · Maximum: 100000000 s
- Timeline scale
New time = old time × scale / 100 + offset.
Enter a percentage, not its decimal fraction: 50 means 50%. Use the unit shown beside this field. %
Minimum: 0.001 · Maximum: 100000 %
Result
- Result
New time = old time × scale / 100 + offset. Apply scaling first and offset second; round to milliseconds. Reject negative times and collapsed cues instead of silently clipping them.
Calculated from your entries using the method below.
- Cues
Reject negative times and collapsed cues instead of silently clipping them.
Calculated from your entries using the method below.
Common mistakes and quick fixes
Scope and common mistakes
Mistake: Treating a result as valid outside the described scope.
Fix: Paste plain-text SRT or WebVTT, up to 100,000 characters. Markup, entities, positioning, STYLE, REGION and NOTE blocks are rejected, not silently removed. Cue starts must be ordered; overlaps are allowed. This is not transcription or a media player. For no speed change use 100%, not 1%; positive offset delays subtitles. A linear transform cannot repair edits or irregular drift. Readability thresholds are your policy, not an accessibility certificate.
Limits and key assumptions
- Paste plain-text SRT or WebVTT, up to 100,000 characters. Markup, entities, positioning, STYLE, REGION and NOTE blocks are rejected, not silently removed. Cue starts must be ordered; overlaps are allowed. This is not transcription or a media player. For no speed change use 100%, not 1%; positive offset delays subtitles. A linear transform cannot repair edits or irregular drift. Readability thresholds are your policy, not an accessibility certificate.
- Displayed results may be rounded; rounding does not add measurement precision.