Your Guide to SIM Card Sizes

SIM cards have been around almost as long as cell phones have. Originally invented in 1991, the first SIM card was the size of a standard credit card. But it wasn’t long before they started getting smaller & smaller to work with different wireless devices, even going fully digital with eSIM (more on that later). This guide will explain the differences between the different types of SIM cards being used today, and help you determine the right size for your phone. 

The different size SIM card sizes

The technical designation for each SIM card size uses the term “FF,” which stands for “Form Factor.” However, we tend to use more general terms to describe the physical dimensions of each SIM card. Let’s do a rundown of all the current SIM sizes and their names:  

What is a Standard SIM card?

A Standard SIM card is rare nowadays, this size was used in much older mobile phones, but is not supported by most current wireless devices. About the size of a credit card, the Standard SIM Card was the first of its kind, developed in Germany in 1991. They aren’t used in modern wireless devices anymore. In fact, when someone says “Standard SIM Card,” they’re more likely referring to a Mini SIM.

What is a Mini SIM card?

The most common SIM card size, although quickly going the way of the Standard SIM, a Mini SIM is often referred to as a Standard SIM card nowadays because it’s the SIM Card size most people are familiar with, being the most used SIM card size during the rise of the cell phone industry. Until 2010, that is.

What is a Micro SIM card?

The Micro SIM card was released in 2010 and tried its best to become the new standard for a couple years. A Micro SIM is actually quite comparable to a Mini SIM—so much so that many wireless carriers offered SIM “cutting” services, for people who wanted to upgrade from a Mini SIM phone to a Micro SIM phone without getting a new SIM card. But it wasn’t long before we got something even smaller.

What is a Nano SIM card?

The Nano SIM card was introduced in 2012, just two years after the Micro SIM, and is still currently the most commonly used SIM card size in modern smartphones today. The Nano SIM is almost all SIM and no card, as you can barely see any plastic edges on a Nano SIM. 

What is an eSIM?

An eSIM (embedded SIM) is a digital SIM card that’s built directly into a device, allowing it to connect to a mobile network without requiring a physical SIM card. Unlike traditional SIM cards (nano, micro, or mini SIM), which are removable and have a physical form, an eSIM is embedded in the device’s hardware. For more information on eSIM and its benefits, check out our What is an eSIM blog. 

Do all phones have a SIM card?

All phones require a SIM (Subscriber Identity Module) to connect to a wireless network, but some do it without the card. Most modern wireless phones do have a SIM card slot, but some also support eSIM, which is a digital-only SIM that is “embedded” in the phone (i.e. not removable). Activating and transferring an eSIM is done digitally, so no SIM card slot to open, no plastic card to insert. 

How do I know what SIM card type I have?

There are a few ways to confirm exactly what type of SIM card your phone takes:

Check physical size
Remove the SIM card from your phone and just take a look at it for yourself.

Check phone model
You can look up the make & model of your phone online and see what the manufacturer says the supported SIM card size is.

Consult your carrier
Contact your wireless carrier and ask them what size SIM card you have in your phone right now. 

That’s the SIMple Truth

Now you know all there is to know about SIM card sizes and how to find yours. We at Ultra Mobile make it easy to switch by providing a free 3-in-1 SIM card to any new subscriber. So, whether your phone takes a Mini SIM, Micro SIM or Nano SIM, we’ve got you covered. And if you want to make the digital leap to eSIM, Ultra Mobile supports that too! As long as your phone does. Click the link below to see if your phone is eSIM-compatible.

Check eSIM Compatibility