Reduced storage capacity after reformatting WD Elements SE 4Tb Ext HD from NTFS to FAT32

Hoping someone can offer a solution. Just reformatted a new 4TB WD Elements SE Ext HD from NTFS to FAT32 on my iMac running OSX Sierra 10.12.6. Followed WD’s instructions from their website exactly. the reformat was reported as successful. However The Ext HD is now showing only 1.8Tb of useable space. How do I ‘win’ back the 2.2Tb that I seemed to have lost? Where did I go wrong?

In case you were wondering. I contacted WD who advised that if I format with ExFAT I will not lose any storage space. Apparently FAT32 gobbles up a huge amount of capacity. So when I reformatted using ExFAT I had the full 4Tb of storage capacity available to me. Hope this may be of some help to others.