Subtitles that actually stay synced
Sync any subtitle file in your browser - even when your reference is in a different language. An English SRT works as a timing reference for subs in any language.
Sync Subtitles Automatically
The best subtitle sync available - free, instant, in your browser.
Drift Correction
Subtitles that start fine and slip 4 seconds by the credits? Source with ad breaks the video doesn't have? SubSync re-aligns every line, not just shifts the whole file.
Auto-Sync with Reference
Upload your out-of-sync SRT and a reference file (another SRT or video). SubSync detects speech regions and snaps every subtitle to the right moment automatically.
Manual Time Shift
Shift all subtitles forward or backward by any amount. Perfect for when audio and video are consistently offset by a fixed delay.
SRT In, SRT Out
Works with SRT subtitle files. Upload your file, sync it, and download a clean SRT - no format juggling required.
Runs in Your Browser
Your subtitle text and media files never leave your device. No accounts required for basic use. Fast, private, and secure.
Download in Seconds
Once synced, download your corrected SRT immediately. The entire upload → sync → download flow takes under 10 seconds.
How SubSync compares
Four ways to fix out-of-sync subtitles. Only one handles drift, FPS, and scene-cuts automatically without installing anything.
- No installation required
- Fix a constant offset
- Fix gradual drift (FPS, accumulation)
- Handle ad-breaks & cut scenes
- Per-line speech alignment (auto)
- No command line needed
- Cross-language reference file
- limitedNo installation required
- Fix a constant offset
- Fix gradual drift (FPS, accumulation)
- Handle ad-breaks & cut scenes
- Per-line speech alignment (auto)
- No command line needed
- Cross-language reference file
- No installation required
- Fix a constant offset
- manualFix gradual drift (FPS, accumulation)
- manualHandle ad-breaks & cut scenes
- Per-line speech alignment (auto)
- No command line needed
- Cross-language reference file
- No installation required
- Fix a constant offset
- limitedFix gradual drift (FPS, accumulation)
- Handle ad-breaks & cut scenes
- Per-line speech alignment (auto)
- No command line needed
- limitedCross-language reference file
Comparison reflects default, out-of-the-box behavior of each tool. ffsubsync handles some drift via FFT but does not detect FPS mismatch or segment cuts.
How to Sync Subtitles in 3 Steps
No accounts, no installations, no complexity. Just upload, sync, and download.
Upload your SRT
Drop your out-of-sync SRT subtitle file into the browser. Takes under a second to load.
Add a reference file
Upload a correctly-timed SRT or a video file as a reference. SubSync reads the audio to find exact speech timings.
Get perfectly synced subtitles
SubSync perfectly aligns every subtitle to speech. Download your fixed SRT in seconds.
Formats supported
SRT, VTT, ASS
Processing time
Runs instantly in your browser
Client-side
Subtitle text and media never uploaded
Languages supported
13 languages and growing
Choose your plan
Start free and scale as you need. No hidden fees, cancel anytime.
Free
Create an account in 10 seconds
- 5 auto-syncs per day
- Unlimited manual tools
- SRT format
Pro
For power users
- 500 auto-syncs per day
- Unlimited manual tools
- All formats
- Priority support
Limited time offer
Lifetime Pro - pay once, use forever
Only for the first 50 users - claim it before it's gone!
Questions & Answers
Everything you need to know about SubSync.
Stop watching subtitles at the wrong time
Upload your SRT and a reference - get perfectly synced subtitles in seconds. Free, no account needed.