The SIM cards that fit into those tiny slots in your cell phone and tell your cellular network to whom your calls are to be charged come in four different sizes. With the only real difference between them the amount of excess plastic on which the circuitry is housed, MicroSIMcutter's new SIM card cutter can cut either mini- or micro-SIM cards into the nano-SIM form factor, allowing a user switching phones to recycle their existing card.
All SIM cards have basically the same circuitry – a microcontroller and small amounts of permanent, rewritable, and random access memory. They come in four sizes, ranging from the credit card sized original SIM card to the nano-SIM card, which measures 12.3 mm x 8.8 mm (0.48 in x 0.35 in). Despite the different sizes, they have the same size and pattern of electrodes, and the electronics are buried under the electrodes. The only difference is how much excess plastic is attached to the active part of the card.
The SIM cards are designed to be backwards compatible, so if you have a micro-SIM card but your cellphone takes a mini-SIM card, you can place the micro-SIM card in a mini-SIM adapter, which just adds on the extra plastic.
However, with most cellphone users more likely to upgrade their phones more often than they switch carriers, the most common problem is removing a mini-SIM card from an old phone, and securing a micro- or nano-SIM card for the new replacement phone.
There have been instructions on the Internet for some years describing how the larger SIM cards can be cut down manually, but this requires steady hands, good scissors, and the willingness to risk demolishing your SIM card. Mobile service providers will also offer to copy data from an old SIM to a new, smaller one, but that involves finding time to physically visit a store.
Now there is another option. MicroSIMcutter is importing a Chinese SIM card cutter that can cut either mini- or micro-SIM cards into the nano-SIM form factor. The owner of a new phone can then reuse their old card rather than ordering a new SIM card with a smaller form factor. Their stainless-steel hand cutter, called the Nano SIM Cutter, punches out the shape of a nano-SIM card. A mini-SIM card fits directly into the punch, while a micro-SIM card is placed in a mini-SIM adapter before inserting into the punch to insure proper alignment.
A quick push on a lever, and your need for a nano-SIM card with the correct authentication data is satisfied. Perhaps not an earth-shaking advance, but innovation and good ideas come in all sizes.
Source: MicroSIMcutter
I don't want to perform micro-surgery!
Worked fine. Took the card from her old Samsung feature phone, trimmed it > up and running fine ever since with the iPhone on T-Mobile.
Caution - check prices. These have sold as high as $50+ various online sources. She got her for less than $10.