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SIM card sizes: Standard, Micro and Nano explained

3rd April 2019

SIM Card Sizes

All phones need SIM cards, but they don’t all need SIM cards of the same size. In fact, there are three different sizes in use, namely Standard, Micro and Nano.

We’ve created this guide to help you tell between them and know which one you’ll need. Plus, you’ll find some advice for what to do if you end up with a SIM card that’s the wrong size for your phone.

What is a Standard SIM card?

A Standard SIM card is, despite the name, not the most common or ‘standard’ SIM card you’ll find. But it was when it launched – hence the name.

The name also reflects the fact that this is the largest type of SIM card available at 15 x 25mm. You could think of it as a full size card while the other two are cut down.

However the chip is the same size in all three. This is the important bit that stores your data, so with a Standard SIM card you just have a lot of plastic around it.

The Standard SIM card is the oldest of them (introduced way back in 1996) and so while it was once used in many handsets, including big-name ones like the iPhone 3GS, it’s rarely used in phones now – some feature phones and very basic mobile phones still use these, as do some old handsets, but most smartphones made in the last five years won’t.

What is a Micro SIM card?

A Micro SIM card is one size down from a Standard card. So it’s a little smaller, coming in at 12 x 15mm. As noted above the actual chip is the same size, so it’s just the bit around it that’s smaller.

Having been introduced back in 2003, this card also isn’t widely in use any more, with most handsets having moved on to newer Nano SIM cards, discussed below.

If your phone is a few years old, but too new for a Standard SIM card, then it might use a Nano SIM, but recent handsets generally don’t. As an example, the Samsung Galaxy S5 launched in 2014 uses a Micro SIM, but the following year’s Galaxy S6 uses a Nano one.

What is a Nano SIM card?

Nano SIM cards are the smallest of the bunch, coming in at 8.8 x 12.3mm, they’re also the newest, having made their debut in 2012. This has almost no border around the chip so it’s hard to imagine SIM cards getting much smaller in future, unless the chip itself is shrunk.

Nano SIM cards are by far the most widely used, so if you’re buying a new phone it’s almost certainly one of these that you’ll need.

Why have SIM cards shrunk?

SIM cards have shrunk primarily because the bits that were removed were essentially wasted space and space comes at a premium in a smartphone. By having a smaller SIM card slot, more space can be freed up for a larger battery or other components, or the phone can be marginally shrunk down.

Is there any other difference between them?

No, it’s literally just the size that they come in and therefore what phones they fit in.

What comes next?

We’re unlikely to get smaller SIM cards in future, as noted above to get much smaller there would need to be a change to the chip itself, since Nano SIM cards already have hardly anything around the chip.

What we will probably start to see more of though is eSIMs. These are embedded SIM cards, which is to say you won’t have a physical card that you need to put in a phone, it will be built in instead. As well as potentially being smaller there are other advantages to these, such as being able to change network without changing SIM card.

A few phones such as the iPhone XS and iPhone XS Max already have one of these (alongside a regular SIM card slot), but not all networks support them yet.

What SIM card size do networks send?

Although a Nano SIM is by far the most widely used by modern handsets, most networks will actually send a Multi SIM, Combi SIM or Trio SIM, which are all different ways of saying multiple SIM card sizes in one.

In most cases that means getting all three SIM card sizes, with perforations for each size so you can easily get it to the size you need. In other words, you shouldn’t need to ask for a specific size or even know what size card you need in advance of ordering one.

What can I do if I have the wrong size SIM card?

If you get a new phone that needs a different size SIM card, or end up with the wrong size for any other reason, your best option is to contact your network and ask them to send a replacement. As noted above, you’ll usually get three sizes in one, so probably won’t even have to request a specific size.

If you can’t wait for that then there are other options. If your SIM card is too small for your phone, then you could buy an adaptor. These are small pieces of plastic shaped like a Micro or Standard SIM with space for a Micro or Nano SIM inside, so you just stick your SIM card in the adaptor and then put that in your phone.

If your SIM card is too big then you can get SIM card cutting tools which help you cut it down to the right size. However, you risk damaging it by doing this, so we wouldn’t recommend it.

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