Instant translation
Native subtitles translated the moment they appear. Zero setup, no account, no waiting.
Live demo — click a language
See it speak your language.
PolySub overlays live-translated dual subtitles on YouTube and any video site — the original stays, your language joins it, synced to the second.
Free to install — sign up to unlock presets, transcripts, and community subtitles.
Today we're making handmade ramen from scratch.
วันนี้เราจะทำราเมงทำมือตั้งแต่ต้น
12:04 / 24:30
What is PolySub?
PolySub reads the subtitles a video already has — or transcribes speech live — and translates on the fly. Original and translation sit together on the video, so you never lose the voice of the person speaking.
- ✓Works on YouTube and any video site with subtitles
- ✓Dual lines — original on top, your language below
- ✓Captions when none exist, via Live Transcribe
- ✓Subtitles from real fans in the community
Made for the videos you actually watch
Interviews, vlogs, lives, lectures — subtitled or not, PolySub keeps up.
AI that gets nuance
PolySub AI handles slang, jokes, and honorifics. Pro includes 2,000 credits each month — about 20 hours of video.
Live Transcribe
No subtitles? PolySub writes captions from speech in real time — and translates them too.
Word lookup
Hover any word to pause, hear it, and see what it means in context. Save it to your list.
Community subtitles
Fan translators publish polished subs for the videos you love. Follow your favorites and send corrections.
Yours, everywhere
Languages, themes, presets, and followed translators sync to every device you sign in on.
Watching in three steps
- 01
Add to Chrome
One click. Open any video — YouTube works out of the box.
- 02
Pick your language
Instant translation starts the moment you choose.
- 03
Go Pro when ready
AI translation, Live Transcribe, warm themes — all on one plan.
A theme for every mood
Dark and light come standard. Pro adds four warm themes — the player stays cinema-dark in all of them.
I missed you so much.คิดถึงมากเลยนะ
Look at the moon tonight.今夜の月を見て。
This one's my favorite.이게 제일 좋아요.
Stay with me a little longer.再多陪我一会儿。
Subtitles with a name on them
When a fan has already translated the video you're watching, PolySub tells you. Apply their version with one click, thank them, follow them — or send a correction that credits you when it's accepted.
- ✓One-time toast when community subs exist for a video
- ✓Author stays credited while their subs are on screen
- ✓Pro Studio: create, preview, publish revision histories
@mai.subsTH → EN · 214 versions · 12.4k thanks
Following@hanguk.lineKO → EN · 96 versions · 8.1k thanks
Follow@sora.fansubJA → EN · 187 versions · 15.9k thanks
Follow
Quick answers
Do I need an account to use PolySub?
No — instant translation works the moment you install. An account adds presets, transcript, community subtitles, and sync.
What happens when Pro credits run out?
Instant translation keeps working without limits. You can add non-expiring top-up credits or buy another Pro period.
Which sites does it work on?
YouTube out of the box, plus any video site with native subtitles. Live Transcribe covers videos with no subtitles at all.