How to Compress a File for Sending

 September 13, 2023

By  Kyrie Mattos

You can make it easier to transfer files over the Internet. For this purpose, the so-called packing files, or in a more professional language, file compression. Whether it is a PDF file, a text document, a project file, or a spreadsheet, we have the ability to reduce the size of the file sent. Packing files gives us several advantages:

  • a compressed file takes up less space on the disk and, therefore, it is easier to upload (downloading a smaller file from the server takes less time),
  • many files can be packed into one file,
  • the packed file can be password-protected,
  • a large file can be split into many smaller ones.

I noticed that a common problem is how to pack files to be sent by e-mail. The compressed file can be sent via any Internet method, e.g., by e-mail or using file-sharing services.

What is file compression?

A compressor program converts the file into a smaller one using a special algorithm. Roughly, the algorithm groups repetitive data and saves it in such a way that it takes up less. The result is a smaller file (called an archive) in a file format typical for the selected compression format, e.g., zip, rar. A zipped file can be opened with a decompressor (in practice, often the same program).

It is worth noting that the compression efficiency is different for different types of files, e.g., a txt text file is compressed much more efficiently than an mp3 music file. So sometimes packing won’t give the expected effect.

Which file compression program is the best?

Personally, I recommend Bandizip, which I’m currently using. It is easy to use, fast, has many personalization options, and is free. I’ve also used 7-Zip and SwifDoo PDF, which are also good programs. Bandizip and 7-Zip programs are similar in terms of functionality, while the SwifDoo PDF program is a dedicated PDF compressor program. The choice is yours.

How to compress a file into any format?

To zip a file, you must have a file packing program installed, e.g., Bandizip or 7-Zip. Programs can pack files, e.g., for formats: 7z, zip. Now, all you have to do is right-click on the file icon you want to compress, and from the context menu, select Compress to file.zip or 7-Zip -> Add to archive. If the program window appears, set the compression options (you can leave them unchanged) and finally confirm with the OK button. At this point, the program will pack your file or folder into a new file. This file is already your zipped file. You will find it in the same folder as the packed file, just with a different extension (e.g., .zip, .7z, depending on the compression method you choose).

In the example, I chose the 7z format, but you can choose a different format. In a similar way, you can zip a whole folder with files. In many programs, the whole packaging process looks very similar.

ZIP compression

It is the most popular format for lossless data compression. Its advantage is e.g. speed, efficiency, and an open license.

How to compress files in zip?

To pack files into a zip archive, use a program that supports zip compression. There are many such programs, and they are called file compressors. In new Windows systems, the archiver is built into the system and to pack a file, just select the “Send to” -> Compressed (zip) folder from the context menu. Of the professional free archivers, I will recommend the aforementioned Bandizip, PeaZip, or 7-Zip.

After installing the program, options to facilitate packing and opening of compressed files are added to the context menu in Windows – after clicking the right mouse button on the file icon, we will additionally see options such as: “Open archive,” “Extract here,” “Add to archive.”

PDF compressing

Unlike the zip format, the PDF format has some limitations. To compress PDF files, you need to use SwifDoo PDF, which is a dedicated PDF compressor and editor. After installing the program, you can use it for free for 15 days.

Password protection of a compressed file archive

To add a password to a PDF, zipped rar, zip, or other format file, select the encryption option in the archive program when creating the archive and enter the password. It will be required when opening a compressed file.

How to unpack a password-protected file without a password? This is a problem as old as computer science. Unfortunately, I don’t know of any effective tool, and I sincerely doubt that there are any. I don’t know if it’s even possible to unpack a password-protected file without having it.

The password is used to encrypt the file, and it can be ridiculously time-consuming to guess it, especially if the password is strong (e.g., contains uppercase and lowercase characters, numbers, and special characters). I recommend that you increase your vigilance if someone is guaranteed to crack or recover your password.

PDF file splitting

One of the advantages of file compression programs is the ability to split files into smaller ones. All of the programs mentioned above (PeaZip, 7-Zip, SwifDoo PDF, etc.) allow you to split files into such formats as zip, tar, gzip. How to split a file? When creating an archive, select the format and the option of dividing the archive into the so-called volumes and select their number or the size of one part of the file. The program will generate smaller files with specific names, e.g., zip.001, gz.001.


There are many ways to share large files over the Internet, but not all of them are created equal. The mentioned useful programs can help you compress most file formats for email. You can use your preferred file compression tool to reduce the file size for better sending and sharing.

Kyrie Mattos


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