sectorsPerCluster = ctypes.c_ulonglong(0)
bytesPerSector = ctypes.c_ulonglong(0)
rootPathName = ctypes.c_wchar_p('C:\\')
ctypes.windll.kernel32.GetDiskFreeSpaceW(rootPathName, ctypes.pointer(
    sectorsPerCluster), ctypes.pointer(bytesPerSector), None, None)
print((sectorsPerCluster.value, bytesPerSector.value))
Determine cluster size of file system in Python