You have bought a new mobile phone, iPhone or iPad, but when trying to insert a SIM card, you will notice that it does not fit into it. Some newer cell phones require smaller micro SIM instead of standard SIM. SIM can be simply exchanged for a Micro-SIM from your operator. On the other hand, most of them wants a fee or signing a new contract. They can either replace the SIM or cut it using special cutter tool. Micro SIM (also 3FF) differs from the SIM (2FF, Mini SIM) only in dimensions. SIM measures 15 x 25 x 0.76 mm, micro-SIM only 12 x 15 x 0.76 mm. You can make MicroSIM from your SIM at home (DIY). You just have to cut the SIM properly as shown below. It is also possible to make nano SIM similar way. If you need to put the Micro SIM card back into the mobile phone with classic SIM slot, just insert it into the adapter, which is just a plastic frame. You can buy it or even do it yourself for example from a credit card.
