That’s because some are optimised for recording high-resolution video, others for running apps and accessing the small files often used on phones and tablets. Sound confusing? Don’t worry. Here we’ll explain how to choose the best microSD card for your device, what all the symbols on the card mean, and recommend the best ones to buy. If you’re in a rush, jump to our top microSD recommendations. If you want to understand what all those symbols mean, jump to our explainer below .
How to choose a microSD card
The first choice is capacity. You’ll want to check how large a card your device will accept. Some dash cams will take up to 32GB only, because that’s the limit of the SDHC standard – but most phones will support up to 256GB, thanks to the SDXC standard, with some supporting up to a massive 2TB. The SD Express standard was announced in June 2018, that’s currently only for full-size SD cards.
Do I need a specific card for a camera or a phone?
Short answer: yes. Longer answer: some cards are so good, they’re capable of recording 4K video in your GoPro but will also give great performance in your phone. The newest standards are ‘V’ and ‘A’, and you’ll see a number after each which represents a minimum standard of performance.
Best microSD for video recording
Basically, if you’re buying a microSD card to record video, you’ll want to look for one with a V10 logo or higher. The number after the V is the guaranteed write speed in megabytes per second (MB/s), although it may be higher than this. To record 4K video, you should aim for at least V30. The SD Association has recommendations for speeds you need for recording at different video resolutions: If there’s no ‘V’ number, check the packaging or specifications to find out the write speed. Watch out because the biggest number is usually the read speed, not write. We explain the V standard in more detail below.
Best microSD for phones and tablets
On the other hand, you might be buying a card to expand your phone or tablet’s storage. Here you need good performance for reading and writing small files. That’s why the other new rating system is ‘App performance’, denoted by an A, followed by a number. It works in a similar way to the video class, and you’ll see an A1 or A2 logo on a card. A1 card allows both storage as well as faster data usage. A step further, A2 operates offers even faster read/write speeds and more advanced overall performance to better suit the ever-advancing phones and tablets. A2 is newer, but A1 cards should be fast enough for running most apps and games.
Which microSD card should I buy?
Stick to the well-known brands which will offer a warranty on their cards. Reputable brands include: Samsung, SanDisk, Lexar, Kingston, Integral and Verbatim, among others. There are plenty of fakes and counterfeit microSD cards, so make sure you buy from a trusted seller. If you see a card on eBay that’s a lot cheaper than you expect it to be, there’s probably a good reason! We’ve shortlisted the best brands and models for you below.
Benchmark results – How the best microSD cards compare
Here’s how all the cards we tested compared. While read and write speeds might be apparent, 4KB read and 4KB write speeds indicate how quickly the card can retrieve small, blocks of data (i.e. 4KB of data) from random places. While that might sound like a strange thing to measure, that process is standard to how storage drives work. This makes it a useful indicator in benchmarks for understanding the card’s overall performance.
Best microSD cards – Our reviews
SD, SDHC, SDXC – what does it all mean?
If you’re shopping for a MicroSD card, you’ve probably come across a number of confusing symbols on the label. Let’s break them down. It’s available in 32, 64, 128, 256, 512GB and 1TB capacities, but specs vary slightly across those capacities. The 512GB card, for example, is rated A2 for app performance, while the others are A1. The higher capacity options also offer V class ratings. However, as we found in CrystalDiskMark, even the 128GB card we tested outperformed all other options including the A2-rated SanDisk Extreme PRO card for 4KB performance, managing 12.4MB/s for reading and 5.3MB/s for writing. We saw fairly decent results for large files with 88.7MB/s read speeds and 81.7MB/s write speeds. The latter is more than enough for recording 4K in consumer cameras. So, whether you need a microSD card for your phone, an action camera or dash cam, the PNY Pro Elite is a great choice with impressive prices. It may not be as fast as the Samsung Extreme PRO (below), but at its price, PNY offers incredible value for money, making it the best overall. Storage sizes available: 32GB, 64GB, 128GB, 256GB, 512GB and 1TB. It’s rated A2, which makes it faster for loading apps and dealing with the stuff necessary for phones and tablets. But with read speeds of up to 170MB/s and write speeds up to 90MB/s, it’s also ideal for 4K video recording in your drone, action camera or dash cam. Unfortunately, most devices are limited to the UHS-I speed of 104MB/s so unless you happen to have one that allows for faster transfer speeds you won’t see that 170MB/s. We only had a standard USB 3 microSD card reader available to test the Extreme Pro on our PC, and that’s the situation most people will be in. We saw a read speed of 94.6MB/s and a more-than-decent write speed of 85MB/s. It managed the fastest 4KB read speeds we’ve seen of 9.9MB/s but write speeds of 3.3MB/s weren’t great. So, while the Extreme PRO may technically be one of the fastest around, most people won’t see noticeably faster speeds than are available from the Extreme Plus or even Ultra cards from SanDisk. So the same advice applies as for the Extreme Plus: buy if you can take advantage of the speeds, but if not you can save and go for an Ultra (or the Samsung Evo Plus). Storage sizes available: 32GB, 64GB, 128GB, 256GB, 400GB, 512GB and 1TB Along with the other types of storage, the microSD cards also get the Rugged branding and the company says they’re built to be the toughest around, able to survive being submerged for 72 hours and temperatures ranging from -25C to 85C. We asked which company actually manufacturers the cards for Manfrotto, but were only told that “we source components and collaborate with extremely specialized partners for some product line ups”. There’s a two-year warranty so you’re protected against any manufacturing defects. Although labeled V30, which means a minimum sequential write speed of 30MB/sec, the Pro Rugged actually reads and writes at 90MB/s and this was bourne out in our tests. CrystalDiskMark reported a read speed just shy of 95MB/s and a read speed a little down on the claim at 88.5MB/s. Both excellent results and made even better at this price which is roughly half the RRP. Though squarely aimed at drones, action cameras and gimbals, you could theoretically also use one of these in your phone or tablet, managing a 4KB read speed was 8.5MB/s and 3.75MB/s for writing. Overall then, the Pro Rugged is much better value than a lot of its rivals so long as you find it discounted on Manfrotto’s site or elsewhere. US visitors can head to Manfrotto US. Available in 64GB and 128GB capacities. We tested the 128GB card, but it’s also available in higher capacities (listed below). The packaging boasts of “Write Speed up to 90 MB/s” and we saw a sequential write speed 84.3 MB/s so it’s not far off the claim. Read speeds weren’t quite up to the 100 MB/s claim but at 88.3 MB/s, you won’t be disappointed given the price of the Evo Plus. For phone and tablet use, you’re more interested in 4KB performance, and here the Evo shines, even though it’s not A1 or A2 rated: it scored 10.5 MB/s when reading and 4.7 MB/s when writing. The score outdoes the A2-rated SanDisk Extreme Pro, making it a strong overall choice for mobile if you can’t get your hands on the PNY option above – and especially if you’re sticking it in a phone that’s capable of recording 4K video. Storage sizes available: 32GB, 64GB, 128GB, 256GB and 512GB. The Extreme Plus managed over 87MB/s and 85MB/s for reading and writing speeds in CrystalDiskMark outdoing even the PNY Pro Elite. In fact, it went even faster in short queue depth test, with 92MB/s for reads and almost 88MB/s for writes. That makes it perfect for recording video in 4K drones and action cameras, or burst photography in a DSLR. It’s also a fine performer for phones and tablets thanks to strong 4KB performance of 9.3MB/s when reading and 4MB/s when writing these tiny files. It’s only held back by its high price per GB. If you need speeds this high, you’ll find better value elsewhere. Storage sizes and prices: 32GB, 64GB, 128GB and 256GB. The Exceria High Endurance microSDXC promised read speeds up to 100Mb/s and write speeds up to 65Mb/s on the box. While the cards didn’t reach those absolute maximums in our benchmarks, it came pretty darn close. Read speeds reached 94.79Mb/s, making it faster than the SanDisk Extreme Pro’s, while write speeds capped at 64.17Mb/s. Athough that’s slower than the Extreme Pro, it’s almost twice as fast as the SanDisk Ultra. 4KB test clocked at 5.71Mb/s and 2.07Mb/s for read and write, respectively. While these aren’t the most impressive figures, it shouldn’t be an issue if you mainly intend to use the card for video storage. In fact, despite the A1 rating and Android compatibility, the Exceria High Endurance is best for surveillance cameras and dash cams. The card offers a whole range of protective features that merits its High Endurance namesake. For starters, you can expect shock resistance up to 5 meters, and temperature tolerances between -25 degrees Celcius to 85 degrees Celcius. It’s also IPX7-rated waterproof and resistant to static shocks. Kioxia offers a 3-year warranty should you run into any issues. Storage sizes available: 32GB, 64GB, 128GB and 256GB. In our CrystalDiskMark testing it managed sequential read speeds of 89MB/s – just a little shy of the 95MB/s SanDisk claims – though write speeds were a more modest 27MB/s. That’s fine for recording full HD video, but falls a little short of what you’d require for quality 4K video recording. If you want to use the card in a phone or tablet (or a Nintendo Switch, for that matter) you’ll probably be more concerned with the 4KB speeds, and this is where the SanDisk Ultra is more impressive, managing to read at 9.4MB/s and write at 2.4MB/s. That’s not the very best out there, but it’s better than most and very solid performance for a card this price. Storage sizes available: 16GB , 32GB, 64GB, 128GB, 200GB, 256GB, 400GB, 512GB and 1TB. Integral’s card isn’t just for phone or tablet users, though. It’s ideal if you have a Nintendo Switch and want to install a whole library of games. Similarly, if you want a huge card for recording HD video on an action camera or drone, it’ll handle that task with ease as well. It’s particularly good for a home security camera that records continuously to microSD. What it can’t do is handle 4K recording. The model we reviewed was rated V10, the lowest of the new video recording standards – but the same card now is marked C10, which is a non-video standard. In our tests, we found it managed a sustained write speed of 19.3MB/s. That’s plenty for Full HD 1920×1080 resolution though. Read speeds are much quicker at 83.6MB/s – a whisker short of the 85MB/s claim. For use in phones and tablets, you should be more concerned about a card’s 4KB file performance. Here, the Integral scored 7.3MB/s for reading and 1.7MB/s for writing. It much lower than SanDisk, Samsung’s and PNY’s scores, so there are better options if you’re more focused on mobile use, but for day-to-day storage, Integral offers great value for money. In a nutshell, each of those denominations suggests capacity, with SD meaning Secure Digital. SD, just on its own, is the oldest and supports up to 2GB of storage. These are now pretty much obsolete. Instead, you’re more likely to see:
SDHC which means SD High Capacity and supports up to 32GB of storage; or SDXC, which means SD Extended Capacity, and supports up to 2TB of data.
What is UHS-I, UHS-II, and UHS-III?
Along with HC or XC, you’ll often see UHS markings in Roman numerals on SD cards and microSD cards. There are three UHS specifications you might see: UHS-I, UHS-II, and UHS-III – though you’ll quite often only see the shorthand Roman numeral noted on the card. This refers to the UHS or “Ultra High Speed” bus speed (a bus is a part on the card, or any computer, that communicates data between components). So UHS bus speed essentially indicates the maximum data transfer, or read and write rates. UHS bus speeds emerged as a response to growing demands for faster speeds, particularly with high-resolution video and large RAW format photography. The higher the number the higher the transfer speed:
UHS-I allows transfer rates up to 104Mb/s UHS-II allows transfer rates up to 312Mb/s UHS-III allows transfer speeds of 624Mb/s
UHS-I cards are the most common of the three, while UHS-III microSD cards is the least common and may not even be supported by your device. It’s always worth checking what standards your phone or camera supports before you splash your cash on a new microSD.
What are Speed Classes?
C2, C4, C6 and C10 Speed Class
You might also see the number 2, 4, 6 or 10 inside a circle (which is actually the letter C!). The number refers to sustained writing speed in MB/s. A microSD card marked Class 10 then means a minimum sustained writing speed of 10MB/s. Keep in mind, it’s just the minimum, and typically the cards can write faster than what’s on the label. Sustained speed matters when it comes to video recording, which requires writing data in a steady stream. The slower the sustained writing speed, the more likely you are to drop frames and lose data. C Classes are pretty much on their way out, though you might still see C10 ratings.
UHS Speed Class
A step up from the standard Speed Class, and more common today, is the UHS Speed Class rating, which handles faster sustained writing speeds. It’s worth noting: “UHS Speed Class” is different from the “UHS Bus Speed Class”. One refers to the minimum sustained writing speeds, while the other indicates the maximum transfer rate. Cards marked with a UHS speed class rating use the UHS bus for data transfer (while C Class cards without the UHS marks wouldn’t), so you’re likely to see both UHS speed class and UHS bus speed symbols on most microSD cards these days. How do you tell the two apart? Well, unlike the UHS-1, UHS-II and UHS-III ratings, which are marked in Roman numerals, the UHS speed class is marked with a U with a number inside it. Quite often, you’ll see a U1 or U3 rating. A faster write speed also means you spend less time waiting between capturing videos and photos.
U1 allows writing at a sustained speed of 10Mb/s U2 allows writing at a sustained speed of 20Mb/s U3 allows writing at a sustained speed of 30Mb/s
Video Class speed
It would be too easy if the distinctions ended there, but there’s also a newer Video Class or V Class – which promises even faster sustained writing speeds for video recording. With the ever–growing appetite for 4K and 8K video, V classes allow continuous writing rates at10Mb/s, 30Mb/s, 60 Mb/s and 90Mb/s. You’ll see this noted with a V beside the corresponding write speed.
Is Class 10 and U1 the same thing?
This is debated, but what’s certain is both allow a writing speed of 10MB/s. You might see microSD cards sporting both the U1 and C10 symbols. Similarly, you might see both the V30 and U3 symbols (as in the image above) – again both indicate a 30Mb/s writing speed. All this confirms is you can expect a sustained writing speed of 30Mb/s and the card is suitable for video recording.
How we test microSD cards
We use CrystalDiskMark 6 to test the read and write speeds of each card. This tests both the sequential speeds (reading and writing large blocks of data) and small-file performance, using 4KB reads and writes. Tests are carried out on our Intel Core i7-based test rig over USB 3.0. We use the full-size SD adapters which come with cards and a Lexar Professional USB 3.0 Dual-Slot Reader. If a card comes with its own USB 3.0 adapter, as with Lexar’s own card, we use that instead. Jim has been testing and reviewing products for over 20 years. His main beats include VPN services and antivirus. He also covers smart home tech, mesh Wi-Fi and electric bikes.
