Convert M4A to MP4, Free
Upload your M4A file and get a MP4 in seconds. No account, no watermark.
How to convert M4A to MP4
M4A is an audio-only container in the MPEG-4 format, typically containing AAC audio. It is commonly used for music purchased from the Apple Music store, podcast episodes, and voice recordings on iPhones. Converting M4A to MP4 adds a video track (typically a static image or black frame) to the audio, which lets you upload audio content to video platforms like YouTube that do not accept audio-only files.
BoltConverter wraps your M4A audio in an MP4 container on its servers. The audio quality is preserved exactly and a minimal video track is added to satisfy the MP4 format requirement.
Upload your M4A file
Click the upload area or drag your .m4a file onto the page. Files up to 100 MB are accepted.
Conversion runs on the server
The M4A audio track is wrapped in an MP4 container with a minimal video stream.
Wait a moment
Most M4A files convert in seconds.
Download the MP4
Click Download to save the MP4 file. Your M4A is deleted from the server after conversion.
Frequently asked questions
Will the audio quality change?
No. The AAC audio track from the M4A is remuxed into the MP4 container without re-encoding. Audio quality is preserved exactly.
Can I upload this to YouTube?
Yes. YouTube accepts MP4 files. The video will show a black or static frame with the audio playing, unless you add a cover image separately.
What is the difference between M4A and MP4?
M4A and MP4 use the same underlying container format (MPEG-4 Part 14). M4A is conventionally audio-only, while MP4 contains video. They are technically the same format with different file extensions and content expectations.
Is there a file size limit?
BoltConverter accepts files up to 100 MB. Most M4A audio recordings and music tracks are well under this limit.
Are my files kept private?
Your file is uploaded over HTTPS and deleted from the server immediately after conversion.