SIM card sizes explained: Mini, Micro, Nano & eSIM

Last update: 04.09.2025

Important findings

Today, there are five common SIM card sizes: Full-size SIM, Mini SIM, Micro SIM, Nano SIM, and eSIM.
SIM formats have become steadily smaller, and the eSIM largely eliminates the physical card.
The basic function of the SIM card remains the same in all sizes, with the main differences being the dimensions, memory, and design.
Nano SIM and eSIM have established themselves as standard formats; older SIM types are hardly used anymore.
Combi SIMs offer several formats in one card, where users can flexibly break out the right size.

An overview of SIM card sizes: Formats & types explained

Without the correct SIM card format, no mobile-capable device, whether private or IoT devices, will work. From Micro SIM to Mini SIM to the digital version, SIM cards are available in different sizes. This article provides an overview of the individual SIM card types, their dimensions, and explains their technical data.

What is a SIM card?

A SIM is a chip card in a phone, tablet, or IoT device that identifies a user or an object in the mobile network. It stores necessary data such as phone number, PIN, network operator, the IMSI, and contacts. SIM is the abbreviation for “Subscriber Identity Module”.

Only with the correct SIM card format can mobile devices log into the mobile network and use the internet. Over the years, the sizes of SIM cards have changed significantly as originally, SIM cards were considerably larger and have become smaller over time. Depending on the device, different SIM card sizes such as Mini SIM, Micro SIM, Nano SIM, or eSIM are used today, however, the actual function remains unchanged: The SIM stores the user identity and enables the connection to the network provider.

These different types of SIM cards exist

With the development of new mobile devices, the SIM sizes have also changed to allow more space for other components, such as the camera or battery. The SIM card format has therefore become progressively smaller over the years. Today, there are five SIM card types: Full-size SIM, Mini SIM, Micro SIM, Nano SIM, and eSIM.

The Full-size SIM: The origin of all SIM formats

The first SIM card type was the Full-size SIM, also referred to as the Standard SIM. It is the size of a credit card (85 × 54 × 0.76 mm) and was used in the first large mobile phones of the 1990s. The SIM card dimension is now completely outdated and no longer plays a role. It is only used as a carrier for smaller formats such as the Micro SIM or Mini SIM.

The Mini SIM: A long-standing classic

The Mini SIM is the successor to the Full-size SIM and, at 25 × 15 × 0.76 mm, is significantly smaller. For many years, this SIM card dimension was considered the standard size. Today, the Mini SIM is only rarely used as modern devices use smaller SIM cards such as Micro SIM or Nano SIM.

The Micro SIM: Smaller and more space-efficient

The next SIM size is the Micro SIM, with dimensions of 15 × 12 × 0.76 mm, introduced in 2003. This SIM card format has been widely used since 2010, particularly by the technology company Apple. The iPad and the iPhone 4 were the first compatible devices.

The Nano SIM: The current standard

The most widely used SIM card type today is the Nano SIM. It measures only about 12.3 × 8.8 × 0.67 mm, making it the smallest physical SIM card size. The plastic frame is almost completely removed, leaving only the chip. The Nano SIM was introduced in 2012 and is currently the most common SIM card format.

The eSIM: The future of SIM cards

The embedded SIM (eSIM) is the newest SIM card dimension. In contrast to physical SIM cards, the eSIM is permanently built into the device and does not need to be replaced. The mobile network operator stores the necessary information externally on the card, and activation is carried out via QR code or provider app.

The advantage: Users can store multiple profiles and conveniently switch between tariffs without having to replace the cards. This SIM card type is spreading steadily, especially in smartphones and increasingly in smartwatches and tablets. In IoT, eSIM cards have already become established and simplify the management and scalability of SIMs.

The next SIM card format is already in development: The iSIM (“integrated SIM”) is built directly into the chipset of a device and is a further development of the eSIM.

The difference between SIM cards in comparison

The SIM card dimensions differ mainly in their size, while the technical component often remains the same. Whilst the chip contains the same basic functions, differences exist in storage capacity and integration. We show the differences between the various SIM cards in the following table:


SIM Card Format	SIM Card Size	Integration	Form Factor	Storage	Introduction
Full-size SIM	85 × 54 × 0.76 mm	Physical	1FF	2–16 KB	1991
Mini SIM	25 × 15 × 0.76 mm	Physical	2FF	32–128 KB	1996
Micro SIM	15 × 12 × 0.76 mm	Physical	3FF	64–256 KB	2003
Nano SIM	12.3 × 8.8 × 0.67 mm	Physical	4FF	64–256 KB	2012
eSIM	6 × 5 × 1 mm	Soldered internally	MFF2	Up to 512 KB	2015

SIM Card Format: SIM Card Size
Full-size SIM: 85 × 54 × 0.76 mm
Mini SIM: 25 × 15 × 0.76 mm
Micro SIM: 15 × 12 × 0.76 mm
Nano SIM: 12.3 × 8.8 × 0.67 mm
eSIM: 6 × 5 × 1 mm

SIM-Karten-Format: Integration
Full-Size-SIM: Physical
Mini-SIM: Physical
Micro-SIM: Physical
Nano-SIM: Physical
eSIM: Soldered internally

SIM-Karten-Format: Form Factor
Full-Size-SIM: 1FF
Mini-SIM: 2FF
Micro-SIM: 3FF
Nano-SIM: 4FF
eSIM: MFF2

SIM-Karten-Format: Storage
Full-Size-SIM: 2–16 KB
Mini-SIM: 32–128 KB
Micro-SIM: 64–256 KB
Nano-SIM: 64–256 KB
eSIM: Up to 512 KB

SIM-Karten-Format: Introduction
Full-Size-SIM: 1991
Mini-SIM: 1996
Micro-SIM: 2003
Nano-SIM: 2012
eSIM: 2015

Cutting a larger SIM card into smaller sizes–is it possible?

Yes, a larger SIM card dimension can be cut to a smaller SIM format, for example, from a Mini SIM to a Micro SIM or Nano SIM. Special SIM cutters or templates are available for this purpose. Great care is essential: An incorrect cut can damage the sensitive chip or result in the card no longer fitting properly into the card slot after cutting. Anyone uncertain should request a suitable card directly from the mobile or IoT provider.

Staying flexible with a Combo SIM and adapter

A Combo SIM is a 3-in-1 SIM. It has the dimensions of a Full-size SIM and contains a Mini, Micro, and Nano SIM. Depending on requirements, users simply break out the appropriate SIM size and insert it into the device.

If the SIM card is smaller than the device slot, an adapter can help. This allows a Nano SIM to be used in a Micro SIM slot. The adapter must fit securely so that the card does not move, otherwise, damage to the card slot may occur. An adapter is usually no longer necessary, as almost all providers now supply modern Combo SIMs.

The correct SIM card dimension for every device

SIM card sizes have changed significantly over time, from Full-size to eSIM. Technically, the functions have remained the same, but the SIM formats and dimensions have become more compact. Physical SIM card types are still the most widely used at present. However, the eSIM is gaining increasing importance, especially for IoT applications, as it offers greater flexibility and scalability.

Frequently asked questions about SIM card sizes

Which SIM card formats are available?

There are five common SIM card dimensions: Full-size, Mini SIM, Micro SIM, Nano SIM, and eSIM. Today, almost only Nano SIM and increasingly eSIM are used.

How can I find out which SIM size I need?

Most modern devices today use a Nano SIM or eSIM. The technical device specifications, the manufacturer, or the provider offers more detailed information. Alternatively, a look into the SIM card slot can help.

Can I cut my old SIM card to use another format?

Yes, larger cards can be cut to a smaller format. However, there is a risk of damaging the chip. Providers often supply Combo SIMs with three SIM card sizes.