1. Upload your MP3 file
Start by dragging and dropping your MP3 file into the upload area, or click to browse your device and select your file in the list.
MP3 to MP4 Converter Online
Convert your MP3 (.mp3) file to MP4 (.mp4) in seconds straight from your browser. No installs. No watermarks. 100 % free.
Rated 4.8 out of 5 based on 850+ reviews
Why choose HappyScribe?
47+ Formats
Convert from MP3 to MP4 but also 47+ other formats.
100% Free
No signups, no fees, no hidden restrictions. Convert MP3 to MP4 directly in your browser for free.
Secure
We take your security seriously. All file transfers use 256-bit SSL encryption.
Online
No installs needed; convert MP3 to MP4 right from your browser, on any device, anytime.
How to convert MP3 to MP4?
2. Choose MP4 format
Next, pick MP4 as the format you’d like to convert your video into. Alternatively, we support +47 formats that you can choose from. When you’re ready, hit the Convert button.
3. Download your converted MP4
Once the conversion is complete, you’ll get a download link right away. Just click to save the file to your device. It’s fast, easy, and doesn’t require any software installation.
What is a MP3 file?
MP3 is the ubiquitous lossy audio format that shrank the music industry onto the early Internet. Employing perceptual coding, it removes frequencies masked by louder sounds, producing acceptable fidelity at 128‑320 kbps. The Fraunhofer team finalised MPEG‑1 Layer III in 1994, but it wasn’t until Winamp (1997) and Napster (1999) that MP3 exploded. Patent pools expired between 2012‑2017, freeing open‑source encoders like LAME. Streaming giants now favour AAC or Opus, yet MP3 remains the safest choice for maximum backward compatibility.
What is a MP4 file?
MP4 (MPEG‑4 Part 14) is the dominant container for online video. Based on QuickTime atoms, it can hold H.264/AVC, HEVC, AV1, AAC, AC‑3, timed text, and fragmented segments for adaptive streaming. Finalised in 2001 and revised in 2003 (ISO/IEC 14496‑14), MP4 became the hand‑off format of choice thanks to the iPod Video and PlayStation Portable. The arrival of HLS and DASH further entrenched MP4, which supports ‘moov’ boxes at either head or tail for progressive download or live streams.
Free Online MP3 to MP4 Converter
Need to convert your audio file from MP3 to MP4? It’s simple. Just upload your file, choose the output format, and click ‘Convert’. That’s it — no downloads, no complicated software, and no hidden costs. Our tool is designed to be fast, secure, and completely free, so you can turn your files into the format you need in seconds.
Whether you’re converting audio for sharing, editing, or playback on different devices, our converter ensures high-quality output every time. After your conversion, you’ll also have the option to transcribe video to text, making it easy to turn your MP4 files into accurate, editable text in just a few clicks.
Frequently Asked Questions
How to open a MP3 file?
Every operating system, car stereo, game console, and smart speaker plays MP3. For editing, Audacity or Pro Tools convert to 32‑bit float internally. To reduce size for podcasts, re‑encode to mono 96 kbps using LAME’s `‑V` variable bit‑rate presets.
How to open a MP4 file?
Virtually every player from Safari and Chrome to Xbox and Roku handles MP4. When editing, DaVinci Resolve and Final Cut Pro will optimise H.264 to intraframe proxies for smoother scrubbing. HandBrake transcodes old codecs like DivX to modern H.264+AAC MP4 profiles.
Other tools