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This article provides instructions on how to compress large files into smaller ones on both Windows and macOS. The extent to which you can compress a file depends on the file type you are working with. For audio, video, or image files, it is best to use dedicated software for editing audio, video, or images. However, keep in mind that compressing these types of files will lead to a loss of quality. For other file types, such as text and databases, you can use compression tools like 7-Zip, WinRAR, or macOS's built-in Archive Utility.
Steps
Using 7-Zip Software for Windows
Download and install 7-Zip. This is a free file compression tool that you can use to compress large files and directories. Follow these steps to download and install 7-Zip:
- Go to https://www.7-zip.org/ in your web browser.
- Click on Download next to the latest version of 7-Zip.
- Open the .exe file from your web browser or "Downloads" folder.
- Click Install to proceed.
Luigi Oppido
Computer Repair Technician & Owner, Pleasure Point Computers
Computer Repair Technician & Owner, Pleasure Point Computers
Did you know? Compression is ideal when you need a file to be smaller in size or if you want to combine multiple files into one folder. For example, if you need to send a 12MB file via email but the email service allows a maximum of 10MB, you can compress the file to 7MB. The recipient can then extract the file to access its content.
Right-click on the file or folder you want to compress. A context menu will appear.
- To select multiple files at once, hold the Control key while clicking on each file.
- Most file types can be compressed, though some files (especially videos and audio) may only compress a small portion because they are already compressed.
Select the 7-Zip option. Additional choices will be displayed.
Click on Add to Archive option. The 7-Zip program will then open.
Select 7z in the "Archive Format" menu. When compressing files with 7-Zip, you have the option to choose from various formats for saving your files. The .7z format, exclusive to 7-Zip, allows the file to be compressed to the smallest possible size.
- The recipient needs software capable of opening .7z files, such as 7-Zip, WinZip, or the built-in Archive Utility on Mac.
- If you're concerned that the recipient may not be able to open the file, you can opt for zip. The ZIP format is universally supported across most devices, and still compresses files into a smaller size.
Select Ultra in the "Compression Level" menu. This option directs 7-Zip to compress the file to the smallest size possible. The level of compression will vary depending on the type of file being compressed.
Select LZMA 2 in the "Compression Method" menu. If this option is not available, try selecting LZMA. This is the most modern compression method, supported on most devices.
Set the "Dictionary Size" to a value that is at least 10 times smaller than your available memory. A larger dictionary size means better compression, but you'll need memory that's ten times the dictionary size. In most cases, 128MB is sufficient as it offers great compression with relatively stable speed.
- For example, if your computer has 8GB of RAM, you can select a dictionary size around 800MB or smaller, which will allow the files to compress and decompress faster.
Select the option to split the file into smaller parts (optional). You can leave the other settings at their default values. However, if the file is large, you have the option to split it into smaller pieces. For example, you can split a 12GB folder into three smaller files that fit on three DVDs. Use the menu below "Split to volumes, bytes" to set the desired size for splitting the file.
- You'll need all the split parts to extract the file. Do not delete or lose any of the split parts.
Click on Ok to compress the file. This action will immediately compress the file using the selected settings.
Use WinRAR for Windows
Download and install WinRAR. This is a free program (for a limited time) that allows you to compress files on Windows. Follow these steps to download and install WinRAR:
- Visit https://www.win-rar.com/download.html in your browser.
- Click the blue button labeled WinRAR 6.02 (version name may vary) to download the program.
- Open the WinRAR .exe file.
- Click Install and follow the on-screen instructions.
Right-click on the file or folder you want to compress. A menu will appear immediately.
- To select multiple files, press and hold the Control key while clicking on each file.
- You can compress almost any file, but some files may only compress slightly.
Click on Add to archive next to the WinRAR icon. This is the icon with stacked books.
Select a storage format. Your options are RAR, RAR5, and ZIP. RAR and RAR5 offer better file compression than ZIP, but you'll need specific software to extract the files (like WinRAR or 7-Zip for Windows, Unarchiver for macOS). RAR5 is the latest version of the RAR format, but older software may not support it. ZIP is the standard compression format and can be opened on any system with ease.
Choose Best (Optimal) in the "Compression Method" menu. This method provides the highest compression ratio, resulting in the smallest file size.
Select the Dictionary Size (Compressed folder size). The default option is pre-selected based on the storage format you choose. A larger dictionary size results in better compression, but the compression (and extraction) process might take longer, and the larger dictionary requires better hardware. You can try a smaller size, perhaps 10 times less memory, or stick with the default if your choice is taking too long.
- For instance, if your computer has 4GB of RAM, you might select a size near 400MB for the dictionary.
Choose to split the file into smaller parts (optional). If the file is large, you can split it into smaller parts. For example, you could divide a 12GB folder into smaller files that fit onto three DVD disks. Use the menu below "Split to volumes, size" to set the size of the parts you want to create.
- Make sure you have all the split files to extract them. Do not delete or lose any of the split files.
Click Ok in the lower-right corner. The file will be compressed immediately after this action.
Use the Archive Utility for Mac
Right-click on the file you want to compress. A menu will appear immediately.
- To select multiple files at once, hold down the Command key while clicking on each file. Then, right-click on the selected files.
- You can compress most types of files on a Mac. The size of the compressed file will vary depending on the file type – for example, compressed image, text, and document files will be smaller compared to video and audio files.
Click Compress (Compress). This action will compress the file into a ZIP format, reducing its size.
- The new file will have a ZIP extension, which is a globally-used compression format that can be opened on almost any system without special software.
- You can simply double-click the file to extract it.
Compress Large Video Files
Download Avidemux. To compress large video files into smaller sizes, you'll need video compression software. Avidemux is a free program that significantly reduces video size and works on Windows, Mac, and Linux. Here’s how to download the software:
- Visit http://fixounet.free.fr/avidemux/download.html in your web browser.
- Click on FOSSHUB next to your operating system.
- Click on the download link for your operating system.
- Open the downloaded file from your web browser or Downloads folder.
- Follow the instructions to complete the installation process.
Open Avidemux. You can find the program in the Start menu or the Applications folder on a Mac.
- After compression, the video's quality will decrease. Experiment with different compression settings to find the best balance between file size and quality.
- Movies downloaded from online sources are often already compressed. Over-compressing can make the file unwatchable or result in minimal size reduction.
- You cannot decompress a compressed video file. Make sure to save the compressed version as a separate file to avoid losing the original.
Load the video file into Avidemux. To do this:
- Click File and choose Open.
- Select the video file from your computer and click Open.
Choose Mpeg4 AVC (x264) in the "Video Output" menu. This format provides the highest compression with the best possible quality.
Select AAC FDK in the "Audio Output" menu. This option compresses the audio to reduce the file size.
Select MP4 Muxer in the "Output Format" menu. This is the most widely used video format.
Click on the Configure button below the "Video Output" section. This is the first option found underneath "Video Output".
Select the Video Size (Two Pass) option in the menu. You will find this option under the "Rate Control" section. This allows you to choose the desired file size for your video compression.
- The larger the file size, the better the quality. Setting a target file size smaller than the original will significantly reduce quality.
- If you're unsure about which size to choose, the default option is a safe bet.
Enter the target file size for the video you want to convert. Avidemux will adjust the settings to bring the video close to the target size, but the result may be slightly larger or smaller than the specified target size.
Click on the OK button. This will take you back to the previous screen.
Click on the disk icon to save and compress the video. This icon is located at the top left corner of the application. You will be prompted to name the video before the compression process begins. The time to complete will depend on the video's length and quality settings.
Compress large audio files
Learn what content can be compressed. You can compress most audio files downloaded from the internet, such as MP3 or AAC files. While compressing these files will reduce their size, the sound quality will suffer. It's best to only compress uncompressed file formats like WAV or AIFF.
Download Audacity. This is a free, open-source audio editing program available for Windows, Mac, and Linux. Here's how to do it:
- Go to https://www.audacityteam.org/download/ in your web browser.
- Click on the installation link for your operating system.
- Open the downloaded file in your Downloads folder and follow the on-screen instructions to install it.
Launch Audacity. You can find the program in the Start menu if you're using Windows or in the Applications folder on a Mac.
Open the audio file you want to compress. Follow these steps:
- Click on the File menu and select Open.
- Choose the audio file and click Open.
Create a mono file (optional). This isn't recommended for music or sound effects with high fidelity, but for voice recordings or other audio clips that don't require high accuracy, converting to mono can significantly reduce file size. Follow these steps to convert your file to mono:
- Click the downward arrow next to the file name in the task area.
- Select "Split to Mono" from the menu.
Open the "Export Audio" window. This will bring up a dialog that allows you to choose where to save your file and the format you want to use. Here's how to do it:
- Click on File.
- Click Export.
- Click Export Audio…
Select a compression format. All formats listed in the "Save as type" menu are compressed formats, except for .wav and .aiff. Your choice of format depends on your needs.
- ".mp3" is a popular choice for music, offering good compression without significantly reducing file quality. It is compatible with most devices.
- ".flac" is a lossless compression format. This option is ideal if you're playing sound on a high-quality sound system but may not be compatible with all devices. The .flac format doesn't significantly reduce file size.
- ".ogg" provides better audio quality than MP3 while maintaining a similar file size, but it isn't supported by as many devices.
Select audio quality. Lower quality will offer higher compression ratios, but the sound quality will suffer.
- MP3: The Medium and Standard options provide a decent compression ratio with average sound quality. The Extreme and Insane options have lower compression ratios but provide better sound quality.
- OGG/M4A(ACC): Moving the slider to the left increases compression, reducing sound quality. Moving it to the right decreases compression, improving sound quality.
- Other file types: Use the dropdown menu under "Bit Rate" or "Bit Depth" to select sound quality/compression ratio. Reducing bit rate/bit depth results in higher compression, but worse sound quality.
Name the compressed file and click Save. This will compress the original file into a new file with the name and settings you've specified. The original file will remain saved on your computer.
Compress large image files
Understand what you can compress. Most images downloaded from the internet are already compressed. File formats like .jpg, .gif, and .png are compressed, and further compression may degrade the image quality. Image compression is only useful when working with images from digital cameras or .bmp files.
- Compressed images cannot be uncompressed. It's a good idea to save the compressed version as a separate file to avoid losing the original.
Learn the difference between "lossless" and "lossy" compression. Two common image compression methods are "lossless" and "lossy". Lossless compression is used when you need an exact replica of the original image, often for technical illustrations, charts, or medical images. Lossy compression is used when the sharpness of the image isn't crucial, and it's commonly used for photographs.
- .gif, .tiff, and .png formats are lossless.
- .jpg is a lossy image format.
Open an image editing program of your choice. Nearly all image editing programs support compression by allowing you to save the image in a different file format. When selecting a compression format, you'll also be able to choose the compression ratio.
- Programs like Photoshop, GIMP, and Paint allow you to save image files in a compressed format. You can compress images using most editing software, but some programs may offer additional options.
- Photoshop is the most popular image editor, but if you don't want to pay for a subscription, you can download and install GIMP for free. GIMP is a feature-rich alternative to Photoshop.
Open the image in the editing program. While each image editor has a different interface, the process for opening a file is generally the same. Follow these steps to open an image in the editing program:
- Click File in the menu bar.
- Click Open.
- Select the image and click Open.
Open the Export menu. This menu allows you to save a copy of the original image in a new format. Follow these steps to open the Export menu:
- Click File
- Click Save As in Photoshop and Paint, or Export As in GIMP.
Choose the format you prefer. In Paint, simply click your desired image format. In Photoshop, select your preferred image format from the options next to "Format". In GIMP, click the Select File by Type menu and choose your preferred image format. The format you select is closely related to the image's nature.
- If you're compressing a photograph, choose the .jpg format.
- If you're compressing an image with fewer than 256 colors, choose the .gif format.
- If you're compressing a screenshot, drawing, comic, or non-photographic image, choose the .png format.
- If you're compressing an image with many layers that you wish to preserve, choose the .tiff format (note that .tiff is not necessarily a compressed format).
Click Save in Photoshop or Export in GIMP. This will save the image in the new format.
Select the quality (if available) and click Ok. Programs like Photoshop and GIMP will ask you to select the quality and compression settings after you click "Export/Save". You can usually use a slider to adjust the compression ratio or image quality.
- Increasing the compression (which lowers quality) results in a smaller file size, but the image may lose sharpness and color detail. You'll need to experiment with the options to find the right balance between quality and file size.
