MAKE microSD CARDS COMPATIBLE WITH ANDROID PHONES

In terms of capacity, there are majorly three types of microSD cards: SD, SDHC and SDXC. SD cards have a capacity up to 2GB and can be used in any microSD slot. SDHC cards have a capacity of 2GB to 32GB and can be used in hardware that supports SDHC and SDXC; while SDXC cards range from 32GB to 2TB and can only be used in devices that support SDXC.

Don't be tempted to buy the one with the largest capacity; you should first check what your device supports. Generally speaking, less expensive Android devices support SD and SDHC cards, meaning you'll be limited to 32GB max. Additionally, according to CNET, the following is a list of a couple of Android devices and their supported capacity: Galaxy S and S7 Edge (200GB), LG V10 (2TB), Moto G 2015 (32GB), Xperia Z5 Compact (200GB), and OneTouch Idol 3 (32GB).

For example, hardware that supports microSDXC slots will not automatically support every size within the microSDXC range. The HTC One M9 officially supports microSDXC but it's physical limit is 128GB, anything larger might not work.

After you've considered capacity, the next thing to consider is speed. The speed class of a microSD card determines how quickly it can write data. MicroSD cards are given one of four classifications: 2, 4, 6 and 10. The numbers assigned to the card typically correspond to the minimum transmission speed of the card. If a card is class 2, it has a minimum transmission speed of 2 Megabytes per second (MB/s). Class 4 has a minimum speed of 4 MB/s, class 6 has a minimum speed of 6 MB/s, and class 10 has a minimum speed of 10 MB/s. The speed class of the card is always directly on the card's label, signified as a number (2, 4, 6, 10) inside the letter "c". You should confirm the speed class your Android device supports before purchasing.

In addition to the standard speed classes mentioned above, there are two Ultra High Speed (UHS) classes. UHS cards are significantly more expensive and are designed to be used with UHS compatible devices. UHS cards typically have a classification of either 1 (UHS-1 Class 1) or 3 (UHS-1 Class 3), with 1 signifying a minimum speed of 10 MB/s and 3 a minimum speed of 30MB/s. The UHS class has two bus types labelled '1' and '2', however the UHS-2 bus type is rare.

MicroSDHC and microSDXC cards can be any of these three classes, since capacity and speed are not directly related. MicroSD card type (SDHC or SDXC) and capacity (GB or TB) are directly labeled on the card. The four speed classes mentioned above have logos to signify their minimum speed, for example Class 10 is the letter C with the number 10 inside. The UHS-1 Class 1 and Class 3 are the letter U with a 1 or 3 inside, respectively. Finally, you may also see a 'I' or 'II' labeled on the card, which references a UHS bus speed.

It's incredibly easy to buy a fake memory card. Be weary of incredibly cheap deals on branded cards from non-reputable sellers, chances are the card is fake. Some of these fake cards carry 'SDHC' marking but list capacities over 32GB. Some list capacities of 256GB but are cheap 4GB cards. To avoid this, it's advisable to purchase your SD cards from a reputable seller.

Additionally, you should equally be weary of cheap no-name brands. Some of the cards from these no-name brands tend to fail and when they do they take all your data with them. For this reason, it is usually safer to buy cards from big brands. You typically can expect better performance and greater reliability from these cards, and you can also get a warranty from them (where your card can be replaced if it fails). SanDisk is an example of a good microSD card brand.