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Add Professional Subtitles to Your Videos, Automatically.

Upload your video, get accurate captions in minutes, fine-tune in our built-in editor, and export as SRT, VTT, or burned-in MP4. Used by 10,000+ creators, media teams, and educators.

No credit card required

99.2% Accurate
50+ Languages
AI-Powered
Fluen Studio — AI subtitle editor
|
99.2% Accuracy Rate
1,500,000+ Minutes Processed
50+ Languages
Powered by leading AI speech engines
OpenAI Deepgram AssemblyAI

Not All Auto-Captions Are Created Equal

Free auto-caption tools get the words roughly right. Fluen gets the punctuation, segmentation, and formatting right too.

Generic Auto-Captions
00:00:02,340 → 00:00:07,120
when we first started looking at the data the patterns were really quite surprising we didnt expect
00:00:07,120 → 00:00:10,800
to see that kind of growth especially in the first quarter
No punctuation · No capitalization · "didn't" missing apostrophe
Fluen
00:00:02,340 → 00:00:05,780
When we first started looking at the data,
the patterns were really quite surprising.
00:00:05,780 → 00:00:10,800
We didn't expect to see that kind of growth,
especially in the first quarter.
Proper punctuation · Sentence-level capitalization · Contractions preserved
Generic Auto-Captions
00:01:12,200 → 00:01:19,400
now open your terminal and run npm install to grab the dependencies you'll see a node modules folder appear that means everything installed correctly next create a dot env file in your project root
One massive cue · No line breaks · 7 seconds of speech crammed together
Fluen
00:01:12,200 → 00:01:15,100
Now open your terminal and run
npm install to grab the dependencies.
00:01:15,100 → 00:01:17,600
You'll see a node_modules folder appear.
That means everything installed correctly.
00:01:17,600 → 00:01:19,400
Next, create a .env file
in your project root.
Smart segmentation · Natural line breaks · Within CPL limits
Generic Auto-Captions
00:02:34,100 → 00:02:40,200
welcome back to the show today we have a great guest thanks for having me I'm excited to be here
No speaker detection · Two people talking, no way to tell who
Fluen
00:02:34,100 → 00:02:37,400
Welcome back to the show.
Today we have a great guest.
00:02:37,800 → 00:02:40,200
- Thanks for having me.
I'm excited to be here.
Speaker change detected · Dash marks new speaker

Subtitles on Your Video in Three Minutes

1

Upload Your File

Drag-and-drop any video or audio format. Fluen auto-detects the language and starts transcribing immediately. Supports MP4, MOV, MKV, AVI, MP3, WAV, and more.

2

Review in the Built-in Editor

Captions are synced to your media and ready to review. AI handles punctuation, speaker changes, and line breaks. Make quick edits if needed. Most files need barely any.

3

Export Your Way

Download as SRT, WebVTT, or burned-in MP4 with custom subtitle styling. Need subtitles in other languages? Translate into 50+ languages right from the export step.

Add Subtitles to Your First Video

Captions So Clean, They Look Hand-Written

1 00:00:04,120 → 00:00:08,340
When we first started looking at the data,
the patterns were really quite surprising.
2 00:00:08,800 → 00:00:12,560
We didn't expect to see that kind of growth,
especially in the first quarter.
Proper commas & periods Correct capitalization Contractions preserved
1 00:01:12,200 → 00:01:15,880
Now open your terminal and run
the install command.
2 00:01:16,400 → 00:01:20,720
You'll see a progress bar appear.
That means everything is working.
Smart segmentation Within CPL limits Readable on any screen
1 00:02:34,100 → 00:02:37,400
Welcome back to the show.
Today we have a great guest.
2 00:02:37,800 → 00:02:41,200
- Thanks for having me.
I'm excited to be here.
Speaker change detection Dash-prefixed turns Multi-speaker support
Try It With Your Own File

Free Auto-Captions Get You Started. Fluen Gets You Done.

YouTube auto-captions are full of errors
99.2% accuracy with proper punctuation and capitalization
One long line of text, hard to read on screen
Smart segmentation at natural sentence boundaries
No way to edit without downloading and re-uploading
Built-in professional subtitle editor with media sync
Only basic SRT export, no styling options
Export SRT, WebVTT, or burned-in MP4 with style control
Translation is a completely separate process
Translate into 50+ languages on the same platform

Your Subtitles, in Any Language

Spanish
French
German
Portuguese
Japanese
Chinese
Korean
Arabic
Italian
Dutch
Russian
Polish
Turkish
Hindi
Swedish

Fluen's context-aware AI translation doesn't just swap words. It re-segments every cue for the target language, respecting character-per-line limits and natural reading flow. The result: subtitles that look like they were written by a native speaker.

Explore Translation Features

Everything You Need. Nothing You Don't.

Multi-Engine AI

We route your file to the best speech engine for your content type, language, and audio quality.

Smart Segmentation

Captions are split at natural sentence boundaries with proper character-per-line limits for readability.

Speaker Diarization

Detects speaker changes in interviews, podcasts, and multi-person recordings automatically.

Custom Glossary

Define how technical terms, brand names, and jargon should appear in your captions.

Subtitle Styling & Burn-in

Full control over font, color, backing plate, and positioning. Generate burned-in MP4s ready to upload anywhere.

Batch Processing

Upload multiple files at once. Queue them up and let Fluen process your entire content library.

Built for Creators Who Make Content Every Week

YouTubers & Video Creators

Boost discoverability and watch time with accurate captions. YouTube rewards accessible content in search and recommendations.

Podcasters

Turn episodes into searchable transcripts and captioned video clips. Repurpose audio content for social media and YouTube.

Course Creators & Educators

Make courses accessible and compliant. Subtitles improve retention and help non-native speakers follow along with your content.

Video Marketers & Agencies

Caption client videos at scale. Deliver professional subtitle files in any format, for any platform, in minutes.

“We tested several services and after checking with native language persons, Fluen turned out to be number one. Good work!”
MW Sweden
“I am really amazed by how accurate the subtitles are. This will be a big help for our videos.”
HT Germany
“Your tool has already been such a lifesaver in my business. Thanks to you and the team for an amazing product!”
CR Wisconsin, USA

Works With All Major Video & Audio Formats

Upload
MP4 MOV MKV AVI MP3 WAV
Output
SRT WebVTT Burned-in MP4 Plain Text
Start free with 3 files. Plans from $29/mo for 150 minutes.
See all plans

Frequently Asked Questions

How do I add subtitles to my video?

Upload your video to Fluen, and our AI generates accurate captions automatically. Review and edit them in our built-in subtitle editor, then export as SRT or WebVTT to upload to YouTube, Vimeo, or any platform. You can also choose burned-in MP4 to have the subtitles embedded directly into your video file.

How accurate are the AI-generated subtitles?

Fluen achieves up to 99.2% accuracy by routing your file to the best speech-to-text engine for your content type, language, and audio quality. Combined with our smart segmentation, captions come out well-punctuated, properly capitalized, and split at natural sentence boundaries.

What video and audio formats are supported?

Fluen supports all major video formats including MP4, MOV, MKV, and AVI, as well as audio formats like MP3, WAV, M4A, and FLAC. If you already have subtitle files, you can import SRT files directly during the caption review step.

Can I burn subtitles directly into my video?

Yes. Fluen can generate a burned-in MP4 with your subtitles embedded directly into the video. You have full control over font, size, color, position, and background opacity, so your captions look exactly how you want them.

Can I also translate my subtitles?

Absolutely. Once you've generated and reviewed your captions, you can translate them into 50+ languages with Fluen's AI translation engine. Translations are context-aware and automatically re-segmented for each target language. Learn more about subtitle translation →

How fast is the subtitle generation?

Most files are processed in minutes. A 60-minute video typically takes 3–5 minutes to transcribe. Processing time depends on file length, audio quality, and the AI engine selected. You'll be notified as soon as your captions are ready for review.

Does Fluen detect different speakers?

Yes. Fluen includes speaker diarization that detects when a new person starts speaking. A dash is prepended to the beginning of the cue to visually indicate the speaker change. This is especially useful for interviews, podcasts, and panel discussions.

Is there a free plan?

Yes. You can sign up and process your first 3 files completely free, no credit card required. This gives you access to the AI captioning engines and the built-in editor so you can evaluate the quality before committing to a plan. See pricing →

Your Next Video Deserves Better Subtitles.

Upload your first file free. No credit card. No commitment. Just professional captions in minutes.

Add Subtitles Free
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