FAT32 maximum partition size is 32GB so you must use a different allocation size to format FAT32 on bigger drives.
If you have a 64Gig drive for example you can still format it with FAT32. Windows will only limit you to exFAT or NTFS. However sometimes you need FAT32 because thats the universal booting filesystem.
Just plug in your oversized USB drive, make sure it has at least a 32GB partition which is seen as a drive letter (if not use a software like Ease Partition Manager to make sure your whole drive has one giant partition – to efficiently pack the drive <- you dont have to do this). Then lets assume it shows up as drive letter D:. Then use either tool below to format it as FAT32.