SD Card space shrinks after writing Kali on it

Hey everybody!

I'm using a Raspberry Pi and my 16GB SD Card became too small so I bought a 32GB SD Card and wanted to start over.
But after I wrote Kali Linux on my SD Card (with Win32DiskImage) I realized that lots of space was missing.
fdisk -l only reports ~7GB of space, the rest seems to be gone.
I was looking about resizing the SD Card but I can't do it on the Pi while it's on, since the Partition I need to resize is the one mounted.

What can I do to gain my full SD Card size? :confused:

Thanks for any help :o

I was having the same problem, however, after several hours of tinkering and searching for answers I was able to correct the issue by doing the following:

First clear all partitions off of the SD card (I did this using Diskpart on windows 7)
Next Format the SD card with a simple volume (I used Diskmanager on Windows 7, all defaults but i unchecked quick format)
Next burn the -rpi2 to the SD card (I used win32diskimager)
Lastly resize the partition (There will be two, mine was /dev/mmcblk0p2, as the first is used as the boot partition) using gparted (I used a Kali vm to do this)