The Storage tab does not always report correctly. Also check by choosing your Mac HD and "Get Info" (command-i). It may be different. Try rebuilding Spotlight index.
How to rebuild the Spotlight index on your Mac - Apple Support
Some of the space may also be from Time Machine Snapshots if you are using a laptop.
About Time Machine local snapshots - Apple Support
After you've freed up some space download Omni DiskSweeper. It can give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. Itcan also show you the precise size and location of all your files..It can also give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. Itcan show you the precise size and location of all your files. It will inventory your disk starting from the files that take up the most space. It can also give you a more accurate read of disk space than Finder or Storage Tab of About this Mac. If you want you can even delete files from OmniDisk Sweeper. But be careful some of the items may be important to your system.
For information about the Other category in the Storage display, please see Apple Support Topic
https://support.apple.com/en-us/HT202867
Also, empty the Trash if you haven't already done so. If you use iPhoto, empty its internal Trash first:
iPhoto ▹ Empty Trash
In Photos: File ▹ Show Recently Deleted ▹ Delete All
Is it normal for os x high sierra to take 80gb of storage on macbook air?
