Nobody mention about `-s` option(?). From `man ls`:

`-s, --size
 print the allocated size of each file, in blocks`

.. so if you list with `ls -s` then you will get number of blocks for each directory and file in current directory. When you summarize it then you will get exactly the same number as in `total:` you see on top of `ls -l`.

Extra: To get block size check [this][1].


 [1]: http://superuser.com/questions/121252/how-do-i-find-the-hardware-block-read-size-for-my-hard-drive