Free MP4 to MP3 converter, no upload

MP4 to MP3, right on your device

Pick an MP4 and get an MP3 in seconds. The converting happens in this browser tab, so your MP4 stays on your phone or computer, and long files are fine.

Free, with no account to make
Your MP4 is never uploaded
128, 192, 256 or 320 kbps

Drop an MP4 to convert to MP3 MP4 files from a phone, a camera or a screen recorder. MOV, WebM and MKV work too. Nothing is uploaded. Choose a video

How to convert MP4 to MP3

Add the MP4
Choose the MP4 from your files, or drag it onto the box. Its sound format and bitrate appear above the player.
Set the MP3 bitrate
Match the bitrate shown for the MP4's sound, or go one step above it. 192 kbps is a safe pick when no bitrate is shown.
Convert
Press Make the MP3. A bar shows how far it has got; the MP4's picture is skipped, so it is quick.
Save the MP3
Press Download. On an iPhone, Safari puts the file in the Downloads folder of the Files app.

Have a MOV, WebM or MKV video, or want to trim the MP4 first? Video to MP3 or Cut a video.

What is inside an MP4

An MP4 is a container: one file that holds a video track and, usually, a sound track, along with the details players need to play them together (MDN). In MP4s from phones, cameras and screen recorders the sound is usually AAC; when you open the file, the tool tells you which format and bitrate it has.

To make an MP3, this page decodes that sound and encodes it again with LAME, the open-source MP3 encoder. The picture is never decoded or saved, which is why the sound of a long MP4 converts in seconds.

An M4A is the same MPEG-4 container holding only sound; audio-only MPEG-4 files take the .m4a extension. So when the MP4's sound is AAC, choosing M4A simply moves that sound into a new, smaller file, untouched.

Matching the MP3 bitrate to the MP4's sound

Converting AAC to MP3 compresses the sound a second time, and the losses of two lossy formats add up (MDN). A higher MP3 bitrate keeps that second loss small, but it cannot bring back what the MP4's own sound left out: a 128 kbps sound track saved as a 320 kbps MP3 is two and a half times the size of a 128 kbps MP3, yet it cannot sound better than the 128 kbps sound it came from. Use the bitrate the tool shows for the MP4's sound as your guide:

Sound bitrate the tool shows	MP3 setting to pick	Why
Up to 128 kbps	128 kbps for speech, 192 kbps for music	Matches the sound; more only adds size
About 160 to 192 kbps	192 kbps	Keeps everything the sound has
About 256 kbps	256 kbps	Keeps everything the sound has
320 kbps or more, or uncompressed (PCM)	320 kbps	The highest bitrate MP3 offers (MDN)
No bitrate shown	192 kbps	A safe middle for music and voice

If you only want the MP4's sound as it is and the player you use opens M4A files, choose M4A instead: an AAC sound track is then copied with no second compression at all.

MP4 to MP3 without uploading

Many online converters send your MP4 to their server, convert it there and let you download the result. Here the converting runs in your browser instead: the MP4 is read from your device in small pieces and the MP3 is written in this tab, so a big MP4 has no upload wait and no copy of it ends up on anyone else's server.

The first time you pick MP3, your browser downloads the MP3 encoder from uncrop.si, about 130 KB compressed (Mediabunny). Nothing about your MP4 goes the other way, and the MP3 carries no title, recording date, location or device details from it.

MP4s with no sound, or more than one sound track

Some MP4s have no sound at all, such as many screen recordings made with the sound off. The tool tells you as soon as you open one, because there is nothing to convert.

An MP4 can also hold more than one sound track, for example two languages. The tool converts one: the main sound track, chosen from whether the file marks it as the default, its place in the file and its bitrate. The tool names the sound it found when you open the file.

If your browser cannot decode the MP4's sound, the tool says so before it starts and offers M4A, which copies AAC sound without decoding it. The video to MP3 page lists which browsers can make MP3s.

Questions

How do I convert MP4 to MP3?

Choose the MP4 on this page, keep MP3 selected, pick a bitrate and press Make the MP3. Then press Download to save it.

Is this MP4 to MP3 converter safe?

Your MP4 is never uploaded: this browser tab converts it, and the only thing downloaded is the converter, from uncrop.si. There is no account to make and nothing to install.

Can I convert MP4 to MP3 offline?

The page needs a connection to open, and to download the MP3 encoder the first time you pick MP3. Once both have loaded, the converting itself happens on your device and needs no connection.

Should I convert MP4 to MP3 at 320 kbps?

Only when the MP4's own sound is 256 kbps or more, or uncompressed. When it is 128 to 192 kbps, an MP3 at the same bitrate or one step above keeps what is there, and 320 kbps mostly adds size.

Can I convert MP4 to M4A instead?

Yes. Choose M4A. When the MP4's sound is AAC, it is copied as it is, so the M4A sounds exactly like the MP4 and is ready almost at once.

Why does it say my MP4 has no sound track?

Some MP4s, such as screen recordings made with the sound off, contain only video. There is no sound to convert, so the tool stops and tells you.

Can I convert an MP4 to MP3 on iPhone?

Yes, in Safari 26 or later: open this page, tap Choose a video and pick the MP4. The MP3 goes to the Downloads folder of the Files app (Apple). Older Safari versions can save M4A.

Sources: MDN, Media container formats, MDN, Web audio codec guide, Mediabunny, MP3 encoder extension, Apple, Where to find downloads on your iPhone or iPad

Open-source code this tool runs on your device: Mediabunny (MPL-2.0), unmodified, reads and writes the video and audio files; LAME (LGPL, source at SourceForge), the MP3 encoder (version 3.100), built without its decoder for the browser by @mediabunny/mp3-encoder (MPL-2.0) and loaded only when the new file is an MP3.