Dealing with moving backups around can be a pain. Which is why I’ve found man of us have zipped the .bak files.
The concern I have is that once we wish to use the backup files, they have to be unzipped which means we get hit with the size of the original backup size again.
So, I recently realised that you can choose to compress a backup as you start up.
You can do this using the Backup wizard in SQL Server Management Studio (SSMS), or using a script.
Using the wizard
Open the Backup wizard
Navigate to Backup options
Under the Compression section, select Compress backup
I tested this theory, and found the following difference:
Uncompressed: 2.79GB Compressed: 1.02GB
So, it seems good to me.
I hope that helps!