Auto Fix Subtitles
Fast. Private. Perfect.
Automatically detect and repair timing overlaps, high CPS, empty cues, and other common subtitle errors in one click.
Drag & drop your subtitle file here
or click to browse
SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, SMI, TXT, JSON
How It Works
Upload your subtitle file. SRT, VTT, ASS, SSA, LRC, SBV, TTML, SCC, STL, and SMI are all supported.
The Auto Fix engine scans your subtitles and reports how many issues were found in each category.
Toggle individual fix rules on or off to control exactly what gets repaired.
Click Fix to apply the selected rules and preview the corrected result.
Download the corrected subtitle file or run another pass with different rules.
Why Choose AllSubConverter?
Your Privacy Matters
Everything runs in your browser. Your files are never uploaded.
Lightning Fast
Optimized processing engine converts files in seconds.
Free & Local
Each file can be up to 50 MB. Batches can contain up to 200 files or 1 GB total.
Works Everywhere
Works on Windows, Mac, Linux, iOS, Android - any modern browser.
What Auto Fix Can Repair
Who Needs Auto Fix?
Broadcast & Streaming Delivery
Automatically fix overlapping cues and high-CPS lines before delivering subtitles to Netflix, Amazon, or broadcast QC.
Fansub & Translation Teams
Clean up timing issues introduced during translation or manual editing so the final file plays smoothly.
Post-Production Editors
Run Auto Fix as a final QA pass before exporting subtitles for delivery. Fix overlaps, empty cues, and timing errors in seconds.
Content Creators & YouTubers
Fix subtitles generated by speech-to-text tools that often produce overlapping or too-fast cues.
Educators & E-Learning
Improve subtitle readability in online courses by fixing high CPS and merging tiny cues.
Accessibility Compliance
Use readability checks and cleanup to reduce overly fast cues and timing overlaps before accessibility review.
Frequently Asked Questions
Auto Fix detects and repairs eight categories: overlapping cues, high reading speed (CPS), empty subtitle entries, tiny cues below a duration threshold, inconsistent punctuation, non-standard quotes, duplicate consecutive cues, and invalid timestamps where end comes before start.
No. All fixing happens entirely in your browser using JavaScript. Your subtitle files never leave your device, making Auto Fix safe for confidential or unreleased content.
When two cues overlap in time (the next cue starts before the current one ends), Auto Fix trims the first cue's end time to the start of the second, ensuring only one subtitle block displays at a time.
Auto Fix shows issue counts and lets you toggle each rule before applying it. Nothing is modified until you click Fix; review the preview and keep your original file if you want to compare results.
CPS measures reading speed: how many characters appear per second of a subtitle cue. Broadcast standards typically recommend a maximum of 15-20 CPS. Auto Fix can extend the duration of high-CPS cues to bring them within a readable range.
Yes. Every fix rule is an independent toggle. You can apply only overlap fixing, only CPS adjustment, or any combination. The preview shows the count of issues each rule would repair.