What a compressed file is and why you need to open it

A compressed file is a folder or document that has been squeezed down to take up less space, usually so it can be sent by email or downloaded faster. The most common type is a ZIP file, which ends in .zip. You will also see .rar, .7z, and .tar.gz files. Before you can use what is inside — whether that is documents, photos, or software — you have to decompress it, which means unpacking it back to its original size.

Your computer probably already has the tool built in to open ZIP files. For other formats, you may need to download a free program. The process takes less than a minute once you know which button to click.

Key Takeaways

  • Windows and Mac both have built-in tools to open ZIP files without downloading anything extra.
  • Right-click the compressed file and select "Extract All" on Windows or "Open" on Mac to unpack it.
  • For RAR, 7Z, and TAR.GZ files, you will need to download a free program like 7-Zip, WinRAR, or The Unarchiver.
  • After you extract a compressed file, a new folder appears in the same location with the unpacked contents inside.

Opening a ZIP file on Windows

Windows 10 and 11 have a built-in ZIP tool, so you do not need to install anything. Find the ZIP file on your computer, right-click it, and look for the option that says "Extract All". Click that option.

A small window will appear asking where you want the unpacked files to go. The default location is usually fine — it will create a new folder in the same place as the ZIP file. Click "Extract" and wait a few seconds. When it finishes, you will see a new folder with the same name as the ZIP file. Open that folder to see what was inside.

If "Extract All" does not appear when you right-click, your version of Windows may be older. In that case, download 7-Zip (free, from 7-zip.org) and use that instead.

Opening a ZIP file on Mac

Mac also has a built-in tool. Find the ZIP file in Finder, double-click it, and it will automatically unpack. A new folder with the same name will appear right next to the ZIP file. That folder holds everything that was compressed.

If the file does not unpack when you double-click it, try right-clicking the ZIP file and selecting "Open With" and then "Archive Utility". If that still does not work, download The Unarchiver from the Mac App Store (free) and try again.

Opening RAR, 7Z, and TAR.GZ files

These formats are less common but work the same way once you have the right tool. Windows does not have a built-in opener for them, so you will need to download one. The most popular free options are 7-Zip (works with 7Z, RAR, and TAR.GZ) and WinRAR (works with RAR and most other formats).

Download and install 7-Zip or WinRAR, then right-click the compressed file. You should see an option like "Extract Here" or "Extract to [filename]". Click it and the file will unpack in the same folder. On Mac, download The Unarchiver from the App Store and double-click the compressed file — it works the same way as the built-in ZIP tool.

What to do if the unpacked folder is empty or damaged

Sometimes a compressed file arrives incomplete or corrupted, especially if the download was interrupted. If you open the unpacked folder and it is empty or shows an error, the file itself is probably damaged. Try downloading it again from the source.

If the file keeps arriving damaged, ask the person or website that sent it to re-upload it. Occasionally a file is too large or complex for the built-in tools to handle — if that happens, try downloading 7-Zip or WinRAR instead, as they can sometimes recover files that the standard tool cannot.

Finding and organizing unpacked files

After you extract a compressed file, look in the same folder where the ZIP (or RAR or 7Z) file was sitting. You will see a new folder with the unpacked contents. Some people delete the original compressed file after unpacking, since you now have the real files. Others keep it in case they need to send it to someone else or want a backup.

If you unpacked a lot of files and they are scattered across your desktop or downloads folder, move the unpacked folder to a place where you can find it later — like a Documents folder or a project folder. The compressed file itself takes up very little space, so there is no harm in keeping both.

Frequently Asked Questions

Can I open a compressed file without unpacking it?

Some programs let you peek inside without unpacking. Windows File Explorer and Mac Finder both let you browse a ZIP file by double-clicking it, though you cannot edit the files inside until you extract them. For other formats, you usually have to unpack first.

What if I do not know what type of compressed file it is?

Look at the end of the filename. It will say .zip, .rar, .7z, or .tar.gz. If you are not sure, download 7-Zip — it handles almost all common formats. Right-click the file and select "Extract" and it will usually work.

Is it safe to open a compressed file from the internet?

Compressed files themselves are safe to open. However, like any file from the internet, scan it with your antivirus software first if you are not sure where it came from. If someone you do not know sent it to you unexpectedly, it is fine to ask them what it contains before you unpack it.

Why is my antivirus warning me about the compressed file?

Antivirus software sometimes flags compressed files because malware can hide inside them. If you trust the source, you can usually tell your antivirus to ignore the warning and proceed. If you do not recognize where the file came from, delete it.