Subtitles out of sync?

Upload your SRT and a reference file — SubSync automatically aligns your subtitles to speech in seconds.

Sync subtitles freeHow it works
3 subtitles
00:01:22:12
01:2201:2401:2601:2801:3001:32
01
"Did you hear that?"
02
"It came from the basement."
03
"We need to get out of here."
Audio

Auto-sync that actually works

FFT + RANSAC + dynamic programming. The same algorithms used by professional tools — free, instant, in your browser.

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Most popular

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.

Drift Correction

Fix subtitles that gradually drift out of sync. Apply linear correction so timing stays perfect start to finish.

SRTREFSRT

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

Everything processes locally — no uploads to servers, 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.

Three steps to perfect sync

No accounts, no installations, no complexity. Just upload, sync, and download.

1

Upload your SRT

Drop your out-of-sync SRT subtitle file into the browser. Takes under a second to load.

2

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.

3

Get perfectly synced subtitles

SubSync aligns every subtitle to speech automatically using FFT + RANSAC. Download your fixed SRT in seconds.

0

Formats supported

SRT, VTT, ASS

<1s

Processing time

Runs instantly in your browser

0%

Client-side

Files never leave your device

0

Languages supported

12 languages and growing

Choose your plan

Start free and scale as you need. No hidden fees, cancel anytime.

No Account

Try it out instantly

Free
  • 3 auto-syncs per day
  • Unlimited manual tools
  • SRT format
Use now
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Free

Create an account in 10 seconds

Free
  • 15 auto-syncs per day
  • Unlimited manual tools
  • SRT format
  • Sync history
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Pro

For power users

Coming soon
  • 500 auto-syncs per day
  • Unlimited manual tools
  • All formats (coming soon)
  • Priority support

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.

Sync Subtitles Free