How do I convert MP4 to M4B?

Drop your MP4 file onto the converter above, make sure M4B is selected, and click Convert. When it's done, download the M4B file — it usually takes a few seconds.

Is it safe to convert MP4 to M4B here?

Yes. MP4 to M4B conversion happens entirely inside your browser using WebAssembly, so your file is never uploaded to any server.

Is the MP4 to M4B converter free?

Yes — free with no watermark. Signed-out visitors can convert 25 files a day, and a free account raises that to 250.

Will converting MP4 to M4B reduce quality?

M4B is a lossy format, but our defaults are tuned to be visually indistinguishable for most files. You can raise the quality under Options.

Can I convert multiple MP4 files at once?

Yes. Add up to 5 files at a time without an account, 10 with a free account and up to 500 on paid plans, then download them individually or as a single ZIP.

MP4→MP3 MP3→M4B MP4→WebP MP4→MOV WAV→M4B MP4→GIF MOV→M4B MP4→WAV M4A→M4B MP4→WebM WebM→M4B MP4→MKV MP4→M4A MP4→AVI MP4→FLAC MP4→AAC MP4→OGG MP4→WMV MP4→Opus MP4→M4V MP4→FLV MP4→MPEG MP4→3GP MP4→WMA MP4→TS MP4→MPG MP4→AIFF MP4→AMR MP4→VOB FLAC→M4B MKV→M4B AAC→M4B AVI→M4B OGG→M4B WMV→M4B Opus→M4B WMA→M4B FLV→M4B M4V→M4B MPEG→M4B 3GP→M4B AIFF→M4B AMR→M4B MPG→M4B TS→M4B MTS→M4B VOB→M4B M2TS→M4B PNG→JPG JPG→PNG PNG→WebP JPG→WebP WebP→PNG WebP→JPG HEIC→PNG HEIC→JPG PNG→JPEG JPG→JPEG JPEG→PNG JPEG→JPG PNG→PDF JPG→PDF PDF→PNG PDF→JPG HEIC→WebP PDF→DOCX DOCX→PDF JPEG→WebP WebP→JPEG PNG→GIF JPG→GIF GIF→PNG GIF→JPG MOV→MP4 WebP→PDF HEIC→JPEG WebP→GIF GIF→WebP HEIC→PDF MP3→WAV WAV→MP3 JPEG→PDF PDF→JPEG SVG→PNG SVG→JPG HEIC→GIF MOV→MP3 GIF→MP4 JPEG→GIF GIF→JPEG PNG→AVIF JPG→AVIF AVIF→PNG AVIF→JPG MP3→M4A M4A→MP3 GIF→PDF SVG→PDF PNG→SVG JPG→SVG PDF→SVG SVG→WebP MOV→WebP WebM→MP4 WebP→AVIF AVIF→WebP WebP→SVG SVG→JPEG MKV→MP4 HEIC→AVIF JPEG→AVIF AVIF→JPEG JPEG→SVG MOV→GIF GIF→MOV WebM→MP3 AVIF→PDF MP3→FLAC FLAC→MP3 AVI→MP4 MKV→MP3 GIF→AVIF AVIF→GIF SVG→GIF GIF→SVG WebM→WebP MOV→WAV XLSX→PDF CSV→PDF EPUB→PDF PDF→EPUB MOV→WebM WebM→MOV MKV→WebP PNG→ICO JPG→ICO ICO→PNG ICO→JPG MP3→AAC WAV→M4A AAC→MP3 M4A→WAV AVI→MP3 MOV→MKV MKV→MOV MOV→M4A DOCX→EPUB EPUB→DOCX CSV→DOCX PDF→TXT DOC→PDF TXT→PDF WebP→ICO ICO→WebP PPTX→PDF AVI→WebP WebM→GIF GIF→WebM SVG→AVIF MOV→AVI

MP4M4B

Convert MP4 to M4B

Free and private: MP4 files are converted in your browser on computers; on phones, in our fast cloud and deleted automatically.

In your browser (fast cloud on phones)
No watermark
Batch & ZIP download

Need a smaller MP4? Compress MP4

How to convert MP4 to M4B

1
Add your MP4 files
Drag and drop MP4 files onto the converter, paste them, or click to browse. You can add several at once.
2
Choose M4B
M4B is already selected. Open Options if you want to change quality, size or metadata.
3
Convert
Click Convert. Your files are converted right in your browser in seconds.
4
Download your M4B
Download each M4B file, or everything at once as a ZIP.

MP4 vs M4B

From

MP4 · MPEG-4 Part 14

MP4 is the most widely supported video container. It usually holds H.264 or H.265 video with AAC audio and plays on every device and platform.

Type: Video
Extension: .mp4
MIME: video/mp4
Best for: sharing, streaming and uploading video anywhere

Lossy compressionOpen standard

All MP4 conversions →

M4B · MPEG-4 Audiobook

M4B is an MP4 audio file flagged as an audiobook, supporting chapters and resume position.

Type: Audio
Extension: .m4b
MIME: audio/mp4
Best for: audiobooks on Apple Books and other players

Lossy compression

All M4B conversions →

MP4 to M4B: frequently asked questions

Free, private and in your browser