Two lines, one glance
The original subtitle sits right above your translation. You follow the story and still hear how it was really said.
New in 5.9 — control it all from the YouTube player
YouTube subtitles, translated the way people actually talk.
Mono Translate Pro puts the original line and your translation together on the video. Professional Translation reads the scene around each line — who is speaking, what just happened, the joke from three lines ago — so the subtitles flow from one line to the next.
- 27 languages
- Works on any video with captions
- Your free Gemini key, added once
What is Mono Translate Pro?
A Chrome extension that translates YouTube subtitles — and helps you keep what you learn.
Install it once. Every video with captions can now play in your language, with the original line still on screen.
A translation that reads the room
Professional Translation looks at the scene, the speakers and the lines around each subtitle before it chooses a single word.
Learn from the videos you love
Save a line, replay the real voice and practise it in Mono Workspace — same video, same moment.
Professional Translation
Line by line is fast. Reading the scene is what makes it good.
Most tools translate each subtitle on its own, like a word list. Professional Translation reads the conversation first, then writes the translation — that is why it lives in Mono Pro.
- It knows who is talkingNames, pronouns and the way people address each other stay consistent for the whole video.
- It hears the toneA joke stays funny, a polite refusal stays polite, and sarcasm doesn't turn into a compliment.
- It finishes the sentenceWhen a thought is split across two subtitles, it is translated as one thought.
- It knows what you are watchingA cooking show, a podcast, a lecture and a travel vlog each get their own voice and vocabulary.
Fast Translation is still there when you only need the gist — instant, with nothing to set up.
Korean food show · two hosts at a night market
- 언니, 이거 진짜 미쳤어요.Sister, this is really crazy.line by line
- 아까 그 집보다?Than that house earlier?line by line
- 비교가 안 돼요. 여기 단골 될 듯.No comparison. I think I will become a regular here.line by line
Each line translated on its own.Translated as one conversation, with the scene in mind.
Your Gemini key
A free key from Google. Add it once, then forget about it.
Professional Translation runs on Google Gemini through your own API key. Creating one takes about a minute in Google AI Studio and costs nothing.
Create a free key
Sign in to Google AI Studio and press “Create API key”. The free tier needs no credit card.
Paste it once
Mono saves the key in your Chrome profile and connects by itself. Close the browser, come back tomorrow — still connected.
Connected
Mono keeps translating
Each Gemini model has its own daily free allowance. When one runs out, Mono moves to the next available model on its own, so a long video keeps going.
Google sets the free limits and may change them. Mono never charges for Google usage — your plan pays for the software, not for translation minutes. How to get your key
Subtitle style
Subtitles that look finished, not pasted on.
Choose the font, size, colour, outline, shadow, background and how each line appears. The original and the translation are styled separately — the way an editor would do it in a video app.
Look
Font
Translation colour
Entrance
Player Dock
Everything you need, right in the YouTube player.
Press the Mono button next to YouTube's own controls. Translate, switch languages, choose what's on screen or restyle the subtitles — even in full screen.
- One tap to translate Start Professional or Fast Translation without opening anything else.
- Any of 27 languages Switch the translation language mid-video.
- Both lines or just one Show the original, the translation, or both.
- Size and position Make lines bigger, smaller, higher or lower in a tap.
Side panel
A calm panel that always tells you what's happening.
The side panel follows your system's light or dark mode and shows each step clearly — no guessing, no spinning in the dark.
- Progress you can trust The percentage moves smoothly and never jumps backwards. If Mono is waiting on Google, it tells you.
- Watch while it translates Translated parts are ready to play before the whole video is done.
- Your recent videos Come back to anything you translated without starting over.
Mono Workspace
Don't just understand the video. Keep the words.
When a line is worth learning, take it to Mono Workspace — a map with three stops for one video moment.
Getting started
From install to your first video in four steps.
- 1
Add Mono to Chrome
Install it from the Chrome Web Store and pin it to your toolbar.
Chrome Web Store - 2
Create your account
Sign up here. Your 3-day Pro trial starts and syncs to the extension by itself.
Create account - 3
Add your free Gemini key
Create it in Google AI Studio and paste it into Mono once.
Show me how - 4
Open a video and press Translate
Pick Professional Translation and watch with both lines.
See the guide
Pricing
One plan, two ways to pay. Your translations are never metered.
Pro pays for the software — the extension, Professional Translation, Mono Workspace and every update. The translation itself runs on your free Gemini allowance from Google.
Free trial
3 days
Free
Every Pro feature, no card needed
- Fast and Professional Translation
- Player Dock and subtitle styling
- Mono Workspace 01 · 02 · 03
Monthly
Billed every month
$8/ month
Flexible, cancel renewal anytime
- Use all Pro features for one month.
- Access the latest features whenever Mono Translate Pro is updated.
- Sign in and use up to 3 devices.
- Cancel renewal anytime; keep access from signup until the end of your billing cycle.
- Email support when you need technical advice.
Annual
Billed once a year
$59/ year
Just $4.92 a month
Save $37 compared with paying monthlyUse all Pro features for one year.
- Use all Pro features for one year.
- Access the latest features whenever Mono Translate Pro is updated.
- Sign in and use up to 3 devices.
- Cancel renewal anytime; keep access from signup until the end of your billing cycle.
- Email support when you need technical advice.
Prices in USDSecure checkout by Dodo PaymentsCancel renewal anytime
Questions
Good questions, straight answers.
What is Mono Translate Pro?
A Chrome extension that shows the original YouTube subtitle and a translation together, right on the video. With Professional Translation it reads the scene around each line, so the translation sounds natural and stays consistent from start to finish. When you want to learn from a video, Mono Workspace keeps the lines you save.
What makes Professional Translation different?
Instead of translating each subtitle on its own, Mono first reads a stretch of the conversation. It works out who is speaking, how they address each other, what kind of video it is and which names or terms keep coming back. Then it translates — so jokes land, sentences split across two subtitles read as one, and a character who says “you” casually doesn't suddenly turn formal.
Why is Professional Translation part of Pro?
Because it is the part of Mono that takes real work to build and keep improving: reading context, keeping names and forms of address consistent, adapting to each genre and each of the 27 languages, and handling long videos without stopping. Pro funds that work. The translation itself runs on your own free Gemini key, so you are never paying per minute.
Is the Gemini API key really free?
Yes. You create it yourself in Google AI Studio with your Google account, and the free tier needs no credit card. Google gives each key a daily free allowance, which is enough for a lot of viewing. Google decides those limits and can change them.
What happens when I hit Google's daily limit?
Each Gemini model has its own allowance. When one model runs out, Mono switches to the next available model automatically and keeps translating. If every model is used up for the day, Mono tells you clearly and continues once Google resets the allowance.
Can I change how the subtitles look?
Completely. For the original and the translation separately, you can choose the font, size, weight, colour, outline, shadow and background, where the lines sit on the screen, and how each new line appears. The goal is subtitles that look like they were finished in a video editor — not text pasted on top.
Monthly or annual — what's the difference?
Same features. Monthly is $8 a month. Annual is $59 a year, which works out to $4.92 a month and saves you $37 compared with paying monthly. Prices are in USD.
Your next favourite video probably isn't in your language. Watch it anyway.
Add Mono to Chrome, open a video, and let the subtitles do the rest.