There is a downside, however - If you compress the same file over and over again using the lossy method, you'll start to notice a reduction in quality since data is being removed each time. This is because the data that's removed is outside of the range humans can hear or see. In fact, music and videos you currently have on your computer have probably been compressed and you don't even notice the missing bits. This is more common with media files like video, audio, and images because they don't really suffer too much from the data loss.

Lossy compression functions basically the same way, but as you can probably tell by the name, it results in some data being permanently lost (not as bad as it sounds). This is mainly used for text and spreadsheets because losing words or data from a document isn't something you want to happen.

This way, when you decompress (unzip/open/extract) the file, it knows how to go back to its original form. The same information is there, but it's simplified to takes up less space (Note that the numbers correspond to the number of times that the previous letter repeats). So, let's get started with some of the basics. So if you have ever wondered 'what does compressing a file do?' then you are in the right place. By compressing a file, data takes up less space, and files can be sent and received a lot more quickly.īut wait, how can you reduce the size of a file without ruining the data? It might sound impossible, but once you know what's going on behind the scenes, it makes a lot of sense. Instead, they are the result of compressing large files into something more manageable. They aren't designated to images, video, audio, or any one type of data. Out of the hundreds of different types of file extensions, compression files like ZIP are unique. There's also a good chance you're not entirely sure how file compression works, which would explain why you're reading this post. If you've ever downloaded something from the Internet (which is pretty likely given the fact that it's 2017), there's a good chance you've come across ZIP files, (or some other type of file compression like RAR or 7Z).

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