For your convenience, sim cards are triple die cut, to allow for all devices to use a card that properly fits their sim card holder. You'll notice in the image below that the Nano fits into the Micro, and the Micro fits into the Standard - The Standard is secured to a full size card. Each portion of the full size card can be punched out, further reducing sizes. If a sim card does not fit in your device, you may need to punch out a different size.