These are the best microSD cards you can buy

A microSD card for your Android phone lets you easily move your files, photos, and music from device to device without having to rely on steady Wi-Fi or costly data. An Android microSD card also lets you load your phone up with more apps, music, and movies, which is especially useful if your device doesn’t come with a lot of internal storage. But which ones are the best? Here’s a good selection from which to choose.

What do all these classes mean for your card?

There are many different specs used to classify microSD card speeds, and most cards have at least two of these classifications in addition to the straight read/write speeds listed for the card. Here’s your cheat sheet to these formats and which ones are better than others:

• Video Speed Class: Indicated by a stylized V followed by numbers from 6 to 90, this class is one of the newer classification systems and was developed specifically for shooting ultra-high-definition video. V30 starts at 30MB/s write speed, V60 starts at 60MB/s write speed, and V90 starts at 90MB/s, but unless your phone shoots 8K video, you probably don’t need a V90 card.
• UHS Speed Class: Indicated by a 1, 2, or 3 inside a U, this class is still used on most cards today. U1 starts at 10MB/s write speed, U3 starts at 30MB/s write speed, and both are perfectly adequate for most Android phones.
• Speed Class: Indicated by a number inside a C, this was the original classification system for SD cards. Class 10 was as high as this class went, 10 MB/s write speed, and practically every card worth buying today is well beyond this speed at this point, so it’s not as helpful an indicator of power/quality these days.

You may notice that all of these specs are focused on write speed — that tends to be the lower of the two rates on an SD card — so if you see a card with a “transfer” speed of 100MB/s but only a U3 class, chances are that card has a read speed of 100MB/s and a write speed of 30MB/s.

For most users who just want to use a microSD to store app data, music, and movies for offline playback, you’ll be perfectly fine with a U1 or U3 card like the Samsung EVO Select. If you’re someone who intends to use a microSD card for shooting copious amounts of photos or 4K video, you might want to spring for a U3/V30 (30MB/s) or V60 card, such as the Lexar Professional 1000x.

Check your phone before you buy

Like just about everything else in a phone, manufacturers have to license specific software for certain microSD card formats to work in their devices, and that’s why some phones like the Galaxy Note 10+ say they take up to a 1TB card. In contrast, other phones might only say they take up to a 128GB card.

In most cases, you can stick a 256GB card in a phone only rated for 128GB and be fine, but I generally try to stick to the rated sizes when it comes to Android micro SD cards so that if something goes wrong, support can’t blame you for using too big of a card. And unless your phone specifically says it can take a 1TB card, don’t waste your money on one, as capacities that high do need a phone rated to handle them.