Partition used and available size in bytes
Solution 1:
If you need the partition size, you should be fine with the command you already mentioned:
parted /dev/sdd1 unit B print
If you need the total file system size, you can use the total numbers given by df:
df -B1 /dev/sdd1
Note that if you sum up used and available space given by df, it will be less than the given total space. This is due to file system overhead, e.g. the journal.
If you want to modify or just have a look on your file system setup consider the tune2fs and dumpe2fs manpages.