We’ve come a long way from the floppy disk, and you can now store terabytes of data on a card the size of your thumb nail. The best micro SD cards are used with all our favorite devices, including phones, tablets, and cameras, and have become so prevalent that even gas stations stock them.
Before you go buying the first micro SD card that crosses your path, however, it may be wise to do some research. At first glance, all micro SD cards may seem alike, but there are subtle differences that can affect their performance. Storage capacity may be the primary feature most people value, but speed and dependability also matter, and the best micro SD cards strike a fine balance without costing a fortune.
Best Micro SD Cards: Important Features
To help you find the best micro SD cards for your phone, camera, or mobile devices we have put together a guide explaining the important features to look for:
- Sequential and Random Speeds. Sequential speed refers to how quickly a micro SD card can read and write large pieces of data, like the demand from a digital camera to quickly store and preserve high-resolution photos. Mobile devices more often require random speed, which refers to the speed with which a card stores and transfers small amounts of data, KBs at a time. A quick sequential speed does not automatically indicate a fast random speed.
- Speed Class. The best micro SD cards come in Classes from 2, 4, 6, and 10, with the Class relating to the card’s minimum write speed in MB/s. A Class 10 card has a minimum write speed of 10 MB/s, for instance, but most cards are much faster than that. These days, consumers look instead for the card’s UHS Speed Class (U1 or U3). A U1 rating means the card is suitable for HD, 1080p video recording. The best micro SD cards are U3, and are suitable for advanced 4K recordings with at least 30MB/s of sustained speed.
- SD, SDHC, and SDXC Compatibility. SDHC and SDXC are formats with extended capacities compared to SD, and most new devices are made to be compatible with them. Older devices may not take these formats, however, so always check the compatibility of your item before purchasing a card. Luckily, adapters are available for a quick fix.
- Storage Capacity. SD cards have a very limited capacity of up to 2GB. SDHC cards hold up to 32GB, and SDXC cards have an incredible capacity of up to 2TB. If your device is not SDXC compatible, you will be limited to using 32GB and smaller cards.
Best Micro SD Cards Comparison Guide
Top 3 Best Micro SD Cards Reviews
High performance equipment, like GoPro Hero line or DSLR cameras, require lightning-fast write and read speeds. This speed is imperative to such equipment’s success, so you need a card that’s both quick and versatile enough to work with different devices. That’s exactly why the Samsung PRO Class 10 Full-Sized SDXC is both consumer’s and our top pick for best micro SD card.
With blazing speeds that leave almost all other cards on the list in the dust, the Samsung PRO Class 10 both reads and writes sequentially at 90MB/s and 80MB/s, respectively. Random speeds are a bit lower, with reviewers clocking random read speed at 10MB/s and write speed at 5 MB/s. This card’s random speed isn’t the best, so if you need one of the best micro SD cards for a phone or mobile device, you can save a few bucks and buy a card with less impressive sequential speed.
Notably, this card is all but indestructible, featuring protection from water, shock, X-rays, and even magnets. It’s also compatible with both SDHC and SDXC formats. We highly recommend this card to those who take 4K video or professional-grade photographs, but admit that it may be overkill for the average customer.
With a near monopoly on the SD card market, it’s no surprise SanDisk has two top contenders on this list. While there are certainly quality competitors like Samsung, Kingston, and Patriot, consumers still place their trust in the pioneering hands of SanDisk for the best micro SD cards.
The SanDisk Extreme MicroSDXC UHS-1 Card costs about the same as the Samsung PRO Class 10, but there are some notable differences. First, while this card’s sequential speeds are competitive with the Samsung PRO Class 10 at 90MB/s read and 80MB/s write, random speeds are much slower at just 5MB/s read and 1MB/s write. This card is not recommended for mobile devices, as there are better choices like the Silicon Power 64GB MicroSDXC UHS-1(U3). Still, it will work very well with both professional and common electronics, and comes with an SD adapter.
If warranties are important to you, the SanDisk Extreme MicroSDXC UHS-1 Card may be a better pick, as it features a lifetime warranty backed by excellent customer service. It’s also water, shock, X-ray, and magnet proof, just like the Samsung PRO Class 10.
Following closely behind its big brother, the SanDisk Ultra MicroSDXC is the less expensive but slower version of the Extreme. Most importantly, instead of a U3 rating like the SanDisk Extreme, the Ultra is only a Class 10, which is still respectable but considerably slower. It is not, for instance, recommended for DSLR cameras or 4K video recordings.
For most consumers, however, the Ultra’s read/write speed of 80MB/s / 15MB/s should suffice for most applications, and can handle full HD. The random speeds, while not optimum, are equal to those of the Samsung PRO Class 10, so for the cost you could easily purchase this card instead for use with mobile devices. This card comes with a 10-year warranty, and is protected from the same environmental hazards as the Extreme.