How to Compress MP3 Files [Mac & Windows] – 4 Best Ways

Compress MP3 files with Movavi’s converter:

  1. Download and install the converter.

  2. Upload your files to the program.

  3. Specify the compression settings.

  4. Compress your files.

Edited by Ben Jacklin

When it comes to maintaining a large audio library, the storage struggle is real. Let’s explore a few methods for how to compress MP3 files on a Mac and PC to make your life easier.

List of the best MP3 file compressors for a Mac & Windows




Windows 7/8/10/11, Mac OS X 10.13/10.14/10.15/11, GNU/Linux

Windows 7 or later, Mac OS X 10.10.5 or later

Any (with compatible browser and broadband Internet connection)

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Way #1 – How to reduce file size of MP3 with the Movavi converter

OS: Windows 7/8/10/11, Mac OS X 10.13 or higher

Movavi Video Converter is an easy-to-use compression and conversion tool for video and audio files. Users can opt for an annual or lifetime license to easily and instantly convert media files to any format. In addition to compressing large files into more compact file formats without losing quality, Movavi Video Converter also includes features to trim and edit files as well. You can even import and convert files from a CD and shrink song files to the point that they fit in an email attachment.

Step 1. Download and install Movavi Video Converter

Download the appropriate version of the Movavi converter. Follow the on-screen instructions and then launch the program.

Step 2. Add an audio file to the MP3 file size reducer

Click the Add Media button and then Add audio in the upper-left corner of the program interface. Choose the audio you want to convert and click Open. You can also add your files to the MP3 compressor using drag-and-drop.

Step 3. Choose the format

In the lower part of the interface, locate the Audio tab, open the MP3 group and choose the preset that best suits your needs. You can choose from various bitrates, but note that the higher the bitrate, the better the quality and the bigger the file size.

Step 4. Define the compression rate (optional)

When you select a preset, the estimated output file size will appear in the file list. If the size works for you, then go right to Step 4. If you want, you can adjust the size manually. To do this, click Compress file. This will open a new dialog box. Move the Quality slider to the desired value. You can click the Convert sample button and listen to a small fragment of your converted audio to check the quality.

Step 5. Start the MP3 compression

First, decide where the converted files will be stored. Click the Save to button at the bottom of the program window and specify the appropriate directory on your computer. You can also stay with the default Movavi Library folder.

Once everything is ready, click the Convert button to start the conversion. The processing will take a little while and, once it’s done, the target folder containing the compressed MP3 files will open automatically.

Way #2 – How to compress MP3 in Audacity

OS: Windows 7/8/10/11, Mac OS X 10.13/10.14/10.15/11, GNU/Linux

Audacity is free open-source audio software. In addition to conversion and file size reduction capabilities, Audacity is also a full audio-editing platform. This freeware platform allows users to record and mix audio tracks, import and export different file types, and it supports multiple bitrates, from 16 to 32 across several formats. While it’s a powerful tool, Audacity isn’t the most intuitive program around. And support can be lacking if you aren’t used to finding help in forums and from other users. If you can get over a bit of a learning curve, and you don’t need much technical support, you might enjoy using this software to compress MP3 files in Windows 10, Mac OS X, or GNU/Linux.

To use Audacity as an MP3 file compressor, follow these steps:

  1. Download, install and launch Audacity.
    Download Audacity

  2. In Audacity, go to the File tab and select Export.

  3. Choose the file format you want for your compressed file.

  4. Go to Format Options. Under Bitrate Mode, choose constant and set your preferred bitrate.

  5. Select the Quality you want and click on Save to compress your music file.

Way #3 – How to reduce MP3 file size in iTunes

OS: Windows 7 or later, Mac OS X 10.10.5 or later

iTunes is Apple’s audio platform. It comes with all Mac computers running Mac OS X 10.10.5 or later, and is compatible with all updated iOS devices. And, while iTunes is an Apple product, it also runs on Windows 10 PCs and older Windows operating systems as well. If you’re a Mac user, this free tool is likely already installed on your computer. PC users can get it as a free download from Apple. This software lets you import, export and convert files to different formats. iTunes is not an editing tool, and its capabilities don’t go far beyond playing audio files and converting them to a few different file formats. So, you can use iTunes for reducing an MP3 to a smaller file size, but it may not be the best tool for most users.

Here are the steps to use iTunes as an MP3 file size reducer:

  1. Open iTunes on your Mac device.

  2. If your file isn’t already in iTunes, browse for it in Finder and drag the file to iTunes.

  3. In iTunes, click on the Edit menu and select Preferences.

  4. Click on the General tab and select Import Settings.

  5. From the Import Using drop-down menu, choose MP3 Encoder.

  6. Select the quality you want for your compressed file. 

  7. Right-click on your file and choose Convert to MP3 in the drop-down menu to compress your file to a smaller MP3 file.

Way #4 – How to reduce MP3 file size online for free with MP3smaller

OS: Any (with compatible browser and broadband Internet connection)

MP3smaller is a free online tool to make MP3 files smaller. Its interface is straightforward, and you can compress an MP3 in just a couple of clicks. However, this tool has a couple of significant limitations that need to be addressed. First, to use MP3smaller, you need to have a strong Internet connection with enough bandwidth to upload your file, run the web app and download your compressed file without waiting for hours. Second, and perhaps more importantly, MP3smaller only supports files up to 150 MB in size.

If your file is within the limits of MP3smaller’s capabilities, you can reduce the file size of your MP3 in a couple of quick steps:

  1. Go to the MP3smaller website.
    Go to MP3smaller

  2. Click on the Browse button and navigate to your MP3.

  3. From the drop-down menu, choose the file size you want.

  4. Click the red Upload File button. 

Summary: How to choose the best MP3 compressor

Now that you have an idea of the top four tools for shrinking MP3 files, let’s talk about the best option for you and your specific needs. While each of the above tools will do the job, some will work better for your purposes than others. For example, if you need to save some storage space on your computer, but you still want to listen to your songs with good audio, you’ll want a lossless option, like Movavi Video Converter, that preserves the sound of the file. But you may have other priorities, as well. We recommend considering these factors as you make your choice for the right method to convert your files:

  • Features and tools: Whether you’re converting MP3 files on a Mac or on a PC, consider what you want the end result to be. Do you need to do a little bit of editing to the length of the file to make a ringtone or add an audio effect to a project?

  • Quality and bitrate options: Are you compressing a file to use in a presentation? Or are you sending a quick audio tutorial to a coworker? In the latter case, you probably don’t mind if the result is a little lossy with slightly lower quality. But, if you need to create a file that’s a smaller size with the same quality, you may need a more robust program with more conversion options.

  • Price: Do you have a budget to spend on an MP3 compressor that will do more for you than just change file types? Or, are you looking for the most cost-effective option, even if it sacrifices some quality?

  • Customer support and training: Some of the programs we’ve discussed here have all of the utility you need, but they may not have the most responsive customer support. If you want the assurance that someone will be there for you if a glitch occurs or if you can’t figure out how to make the program work, you should probably opt for a program that’s known for its customer service and a large library of user resources and videos.

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