A number of devices require a microSIM card rather than a traditional full size one including Apple’s iPhone 4S. Although you can request a microSIM from your mobile operator it’s easier and quicker to make your own.
A guide to converting your existing SIM card into a microSIM
The only difference between a regular SIM card and a microSIM is the size. Therefore you can use your existing SIM card to make a microSIM. A normal SIM is 15 x 25mm and simply needs to be trimmed down to 12 x 15mm.
If for some reason you wish to use the homemade microSIM in a device that takes a full size SIM card you can get an adapter to slot it into.
Place your SIM card next to a ruler and mark where you need to cut with a pencil or pen. Mark the SIM to be 12mm on the shorter side and 15mm on the longer side, using a microSIM as a template if possible. If you can, mark lines to cut the SIM from the bottom and left hand edges for a minimum amount of cuts. Depending on the size and location of the contact area on the card, you may need to adjust cuts to avoid cutting through the metal (see our finished result). Under no circumstances should you cut through the contact area.
Carefully cut the SIM card down to size with a pair of scissors or a craft knife. You can discard the cut-offs.
Cut the top right hand corner off the SIM card at the same angle as it was previously. Use the off-cut as a template.
Note: SIM cards vary so you may need to cut specifically around the contact area. Some older SIM cards have metal contacts too large to be cut down to microSIM. An alternative method is to buy a microSIM cutter which works like a hole punch.