MicroSD card slot stock photo 4
Edgar Cervantes / Android Authority

Many of us quickly run out of space on our cameras, laptops, phones, or game consoles. Additional storage is available in many forms, from high capacity external hard drives to the ultra-portable USB flash drives. If you’re looking to boost your smartphone or camera storage, however, a microSD card is the best way to go. With the right adapters, you can use these storage cards with laptops and gaming consoles as well. Here’s everything you need to know about microSD cards and the best microSD cards you can buy.

Looking for even more phone accessories? We have a guide for that!

What to look for

You can always buy a card that is compatible with your device and offers the highest storage and fastest data transfer speeds. This can get really expensive though. You certainly don’t need a card capable of capturing 8K drone footage to save memes on your smartphone. Here’s what to look for when buying a microSD card.


Most smartphone makers dropped support for expandable storage a few years ago, particularly with flagships. While this highly-coveted feature has made a strong return, there are some phones that don’t come with expandable storage capabilities. Check the specs of the phone you want to buy to make sure it is available. You can also make things easy and check out our roundup of the best phones with expandable memory!

Storage capacity

You should try and figure out your capacity needs. It’s tempting to buy a 1TB microSD card and never have to worry about storage again. However, this will set you back hundreds of dollars, when a $25 microSD card with 128GB of storage would have done the trick.

You have to be aware of device compatibility as well. This is not about whether it supports microSD cards, but the type of card you can use. Some phones, especially those that are ultra-affordable, may support microSD cards with a capacity of up to only 32GB. You usually won’t run into the same problem with mid-rangers and flagships, but it’s information worth knowing before making a purchase.

The numbers and symbols on a microSD card explained

phones with expandable memory

You’ll notice a lot of numbers, symbols, and letters on a microSD card. Knowing what they mean is important because it makes it much easier to pick the right option for you.

Speed class: 2, 4, 6, 10, U1, U3

Speed classes are used to show the write speeds of a MicroSD card. You’ll see numbers like 2, 4, 6, 10, U1, and U3 (with the number inside the U). This tells you what the minimum write speed is (10 = 10Mbps), but remember that the theoretical maximum can vary from card to card. Of course, faster is better but is also more expensive.

Anything below class 10 is no longer worth considering. A microSD card for your mobile phone should ideally be class 10 U1. You’ll have to get something with a video speed class if you plan to shoot high-quality videos.

Video speed class: V6, V10, V30, V60, V90

A V, followed by a number, usually indicates the video speed class of a microSD card. So, a V30 card will support a minimum write speed of 30Mbps. You will find video speed class ratings of V6, V10, V30, V60, and V90. Cards with video speed class labels are also designed to support high video resolutions like 4K, 8K, 3D, 360-degree, and virtual reality.

You might need one for your smartphone, depending on what it’s capable of. However, a card with a video speed class rating is a must for most DSLRs, action cameras, and drones.

App performance class: A1, A2

The App Performance Class denotes the MicroSD cards that are best for smartphones and tablets. The A1 and A2 rating means that the card can open apps and process apps quickly. The A2 rating more than doubles the minimum read and write speeds available with cards rated A1.

Read speeds

A microSD card’s read speeds are expressed in a few different ways. Some just put the theoretical maximum, in Mbps, on the card. You might see an XXXX scheme on some cards instead, such as 633x or 1000x. This dates back to the days of CD-ROM drives, where 1x is 150kbps. So 633x means a theoretical read speed of 95Mbps and 1000x means a maximum of 150Mbps. Not many use this scheme anymore, but it’s something you’ll see on Lexar microSD cards.

Storage capacity: 32GB to 1TB

The most prominent information on a microSD card is the storage capacity. The large print with a number is hard to miss and tells you what you need to know. Keep in mind that a 256GB card won’t give you exactly that amount of storage, since the file system takes up some space.

Card type: SDHC or SDXC

MicroSD cards all look the same, but there are a couple of types to be aware of. MicroSDHC (Secure Digital High Capacity) cards are low capacity options with 4GB to 32GB. On the other hand, MicroSDXC (Secure Digital Extra Capacity) cards offer anything above this, within a range of 64GB to 1TB. An ultra-affordable phone or a much older device might only support microSDHC cards, but you don’t have to worry about the card type for the most part.


Another speed rating is the UHS BUS Speed. Most microSD cards will have the roman numerals I or II on it. It’s something you’ll mostly see on U1 or U3 cards. UHS-II offers much faster theoretical speeds and comes with a different pin layout on the card’s back. Something to keep in mind is that backward compatibility isn’t an issue. If you add a UHS-II card to a device that only supports UHS-I, it will still work without the speed benefits.

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Sandisk Ultra: The best microSD card for smartphones

sandisk ultra 65gb micro sd card

Sandisk was one of the first companies to introduce microSD cards with the A1 rating. These Class 10 UHS 1 microSD cards are some of the best options if you are looking for fast app performance. The 16GB and 32GB versions of their Ultra range of microSD cards offer maximum transfer speeds up to 98Mbps, while the higher storage versions, going all the way up to 512GB, bump that up to 100Mbps.

Samsung EVO Select: The best microSD card for cameras

samsung evo select 128 gb micro sd card

The Samsung EVO Select are Class 10 UHS 3 microSD cards that offer storage capacities starting from 32GB all the way up to 512GB. They offer up to 100Mbps read and 95Mbps write speeds. These cards are ideal for those that need to record 4K footage, with the largest storage option giving you room for up to six hours of 4K video.

Sandisk for Nintendo Switch: The best microSD card for the Nintendo Switch

The best microSD card to get for the Switch is the one that gets the official stamp of approval from Nintendo. You can store downloaded games, screenshots, and video captures in the same place, and never have to worry about running out of space on the console. The Sandisk microSD card for the Nintendo Switch offers read and write speeds of up to 100Mbps and 90Mbps, respectively.

Lexar Professional: The best microSD card for drones

The Lexar Professional is the best microSD card for anyone with a drone or action camera capable of shooting high-resolution video. This card utilizes UHS-II technology to offer incredible read speeds of up to 270Mbps with supported devices. Its V90 video speed class ensures a minimum write speed of 90Mbps.

MicroSD cards with the most storage

Sandisk Extreme

If you want the most storage you can get, there are only a couple of options available right now. The first is the 1TB microSD card from Sandisk. The Sandisk Extreme offers fantastic read speeds of up to 160Mbps, while the write speeds max out at 90Mbps. It’s also 4K-ready and rated A2 for app performance. The 1TB Sandisk Extreme is the price of a mid-range smartphone, but can single-handedly cover all your storage needs.

PNY Pro Elite

The Pro Elite by PNY is the second option that comes with a 1TB storage. It ticks all the right boxes and is a great card to get for 4K video recording and app performance. It’s significantly cheaper than the Sandisk Extreme but falls short with its 100Mbps read speeds. Nevertheless, it is still plenty fast for most people’s needs.


Q: Can I use a microSD card with a device that only supports SD cards?

A: Yes! Most microSD cards come with an adapter that lets you easily slot it into devices like DSLRs that require full-sized SD cards. Obviously, a full-sized card will not fit in a microSD card slot.

Q: Will a microSD card work with my PC?

A: It depends on the model. Some new laptops come with built-in microSD or SD card slots, making using a card with the PC much easier. Alternatively, you can pick up a micro SD card reader, like these from Sandisk (microSD only) and Anker (microSD and full-sized SD).

Q: My microSD card isn’t working with the Nintendo Switch. What can I do?

A: A microSDXC card that offers storage of 64GB and above is generally the type of card you’ll buy for the Switch. However, support for this card type isn’t available out of the box, and you might need to perform a software update first. Nintendo has a useful guide on how to do so.

Q: Can I use the same card with different devices?

A: One of the advantages of a microSD card is that you can easily transfer data from one device to another, say if you want to move pictures from a camera to your laptop to edit them. Compatibility shouldn’t be an issue for the most part, but some problems with storing files might occur.

Q: Will the card be safe?

A: A lot of good microSD card manufacturers ensure that their products are shockproof, temperature proof, waterproof, and x-ray proof. If anything goes wrong, most OEMs offer long-term, or even a lifetime, warranty. However, any data stored will likely be lost in case there is any damage.