SIM card sizes: standard, micro and nano explained

When talking about the three types of SIM cards, there’s only one thing that’s different between them: the size.

And when it comes to size, it only means one thing: the amount of plastic around the chip. In fact, the chip is the same size in all three SIMs.

What is a Standard SIM card?

The first SIM card on the scene, the Standard SIM dates all the way back to 1996.

As well as being the oldest of the bunch, it’s also the largest, coming in at 15 x 25mm.

Despite its name, Standard SIMs are quite rare these days – most smartphones no longer use this size of SIM.

What is a Micro SIM card?

Measuring 12 x 15mm, the Micro SIM is smaller than the Standard SIM.

It made its debut in 2003, so it’s also fairly old. Like the Standard SIM, it’s not widely used anymore.

To illustrate, the iPhone 4 uses a Micro SIM, but the iPhone 5 uses a Nano SIM.

What is a Nano SIM card?

Introduced in 2012, the Nano SIM is the most recent and smallest version of SIM card.

It measures a mere 8.8 x 12.3mm, and there’s almost no blank plastic around the chip.

These days, it’s by far the most common and widely used SIM size. If you have a modern handset, it most likely uses a Nano SIM.

To give some examples, Apple has been using Nano SIM cards since the iPhone 5 in 2012, while Samsung’s had it since the Galaxy S6.

What size SIM do I need?

If you’re getting a SIM card for your phone, you’ll probably need a Nano SIM.

If you’re not sure which SIM you need, don’t worry. Most networks send out a Multi SIM (also called a Combi SIM or Trio SIM), which is a SIM card that contains all three sizes. Once you’ve figured out the size you need, you can use the perforated lines on the card to pop out the correct size.

This means you can order a SIM card in advance, without needing to specify the size you want.

What is an eSIM?

While it’s unlikely SIM cards will get smaller than Nano-sized – unless the chip itself changes – there could be a potential shift towards eSIMs.

An eSIM is an embedded SIM card that’s built into your phone. This way, you won’t have to put a physical card in your phone, and it frees up space inside your phone for things like a bigger battery.

What’s more, it allows you to change networks without having to change SIM card.

Right now, eSIMs aren’t that common. Nevertheless, there’s a growing number of phones adopting eSIMs – companies like Apple, Samsung and Google have all included eSIMs in some of their latest handsets.

Not all networks support eSIMs just yet, so thankfully all these devices also include a normal SIM card slot.

SIM card dimensions

• Standard SIM: 15 x 25mm
• Micro SIM: 12 x 15mm
• Nano SIM: 8.8 x 12.3mm

Recommended SIM-only deals

If you’re happy with your current phone, or plan to buy a new one, you’ll need a SIM-only deal.

It’s the cheapest and most flexible option. Rather than being tied to a 12-month or 24-month contract to pay off a handset, you can get one-month rolling contracts for a SIM card with a monthly allowance of data, minutes and texts.

Budget networks like Asda Mobile, giffgaff, iD Mobile and VOXI all offer affordable SIM-only deals.

You can also compare SIM-only deals with other networks such as Lebara, Three, Vodafone, iD Mobile, and O2 with MoneySuperMarket.

When choosing a deal, think about how much mobile data you’ll need per month, as well as how many minutes and texts you want (many deals offer unlimited calls and texts).

Why are SIM cards getting smaller?

The space inside a phone is valuable. By cutting down on the size of SIM cards, manufacturers can make space to fit more important components, such as bigger batteries or more powerful processors.

Other than size, are there any differences between SIMs?

Not at all – aside from their dimensions, SIM cards are exactly the same. The only difference is the size of the plastic around the chip, and therefore which phones they’ll fit.

Do you need different SIMs for phones and tablets?

Not anymore – nowadays, you don’t need to get a special type of SIM for your tablet.

You’ll be able to use a normal mobile SIM in most devices. It's worth considering a data-only SIM, as you won't need any calls or texts.

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

If you have the wrong size SIM for your device, the best thing to do is get in touch with your network and ask them to send a replacement.

You can also take matters into your own hands, if necessary. If your SIM card is too small for your phone, you can buy an adaptor. This is a small plastic frame shaped like a Standard or Micro SIM, which you can slot your Micro or Nano SIM into so it’ll fit in your phone.

It’s more tricky if your SIM card is too big. While there are SIM card cutting tools you can use to trim your SIM to the right size, you risk damaging it.