Free tools

Convert MP3 to MP4 online

Turn an MP3 into an MP4 video right in your browser. Choose a still image or a solid color for the picture, create the video, and download it. Free, no signup, and the audio never leaves your device.

Drop an audio file or click to choose

Free · no signup · runs in your browser · nothing uploads

MP3, WAV, M4A and more · up to 200 MB and about 3 hours · 1280 × 720 MP4

Choose audio

Want the words, not just the clip?

Try a speaker-labeled preview of up to 5 minutes from your audio or video before creating an account, then get another free preview of your first upload in the app.

Get 30 free minutes

Why is this free? Hushscript runs it entirely in your browser. No server processes your file, so there's nothing to charge for.

How to convert MP3 to MP4

Choose an audio file, pick a background, then select Create video and download the .mp4. This free MP3 to MP4 converter makes the video on your device: it adds your picture to the sound and writes the result as one MP4 file, with no signup and no upload.

Pick an image or a color for the video

An MP3 has sound but no picture, so the MP4 needs one. Choose a still image, such as cover art or a logo, or a solid color from the color picker. The picture stays the same for the whole video. Images are fitted inside a 1280 by 720 frame, with black bars if the shape does not match.

Convert WAV to MP4 or M4A to MP4

The same steps turn a WAV or an M4A into an MP4. If the audio is already AAC, which is common for M4A, it is copied into the video unchanged. MP3, WAV and other formats are encoded to AAC with a 192 kbps target. OGG and FLAC work too. If another format fails, convert it first with the audio converter.

A video with a still picture is an easy way to post a podcast clip, a song or a voice message where only video is accepted. The output is H.264 video with AAC audio, which video sites and most editors read. Trim the sound first with the audio cutter, or turn an existing clip back into sound with video to audio. For a video you already have, use the video converter.

Free, and your audio stays on your device

The conversion runs in your browser, so the audio and the image are not uploaded for it. Files up to 200 MB and about 3 hours are accepted, within what your browser and device memory can handle. Keep the tab open while the video is created, and check the download before you publish it.

Need a transcript of the audio?

If you want the words as well as a video, transcribe the audio. Transcription is a separate service that uploads the audio and requires an account.

Updated: October 18, 2026

Frequently asked questions

Is this MP3 to MP4 converter free?

Yes. Making a video from one local audio file here is free and needs no account. The video is created in your browser, so the audio is not uploaded.

Can I convert WAV or M4A to MP4 too?

Yes. The picker takes MP3, WAV, M4A and other common audio files. A WAV to MP4 or M4A to MP4 conversion works the same way: choose the file, choose the background, create the video.

Will the MP4 have any moving picture?

No. An audio file has no picture, so the video shows one still frame for its whole length: your image or a solid color. The frame is 1280 by 720 pixels, and an image that does not match that shape is fitted inside it with black bars.

What happens to the audio quality?

If the file is already AAC, such as most M4A files, the audio is copied into the MP4 without re-encoding. Other formats, including MP3 and WAV, are encoded to AAC with a 192 kbps target, so the sound can differ slightly from a lossless source.

Is there a size or length limit?

The audio file can be up to 200 MB and about 3 hours long, and a background image up to 30 MB. Long files also depend on the memory your browser and device can spare, so keep the tab open and expect long audio to take a while.

Can I use the MP4 on YouTube or in a video editor?

The output is a standard H.264 and AAC MP4, which video sites and most editors accept. Check the downloaded file in the app where you plan to use it.

Can I get a transcript of the audio instead?

Yes, through Hushscript's separate transcription service, which uploads the audio and requires an account. Eligible personal accounts can receive 30 free minutes once after successful card verification, or with their first purchase if not already granted.

Need the words? Transcribe it with 30 free minutes

Preview up to 5 minutes before you create an account, and a new personal account gets a free preview of its first upload in the app. Full transcription needs an account and minutes; eligible personal accounts get 30 free minutes once, after card verification or with a first purchase. No subscription.