Reset SD card

[nickbouwhuis]

I flashed an Raspbian image to my SD card, but I am ready to reformat my SD card. The size is however 70 MB now (instead of 16GB)

How can I restore this?

[Wheel_nut]

That is because you are only seeing the Boot partition, the main partition being ext4 format and invisible to Windows.

If you are putting a new Image on the card using Win32DiskImager, just let Win32DiskImager overwrite it. It will do the re-format on the fly.

If you want to use the card as a FAT data card, the easiest way is to format it in a Digital Camera.

[BerryPicker]

I'm not sure if this is what you're wanting to do, but take a look at
http://elinux.org/RPi_raspi-config
and the option
EXPAND-ROOTFS - Expand Root Partition to Fill SD Card.