Launch GParted
Change the drop-down to the device of the SD card
Right-click on the partition to re-size, select "Unmount"
Right-click on the partition to re-size and click "re-size/move". Drag the end(s) to expand the partition to occupy the entire device.
Click on the check-box to "make these changes"
Wait.
Your SD card will now use all of the space available.
Change the drop-down to the device of the SD card
Right-click on the partition to re-size, select "Unmount"
Right-click on the partition to re-size and click "re-size/move". Drag the end(s) to expand the partition to occupy the entire device.
Click on the check-box to "make these changes"
Wait.
Your SD card will now use all of the space available.