MicroSD cards are ubiquitous these days and they're used in many devices, chiefly phones. But you'll want to pick a different microSD card for your phone than a device with a camera such as a dash cam, drone or action camera.
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? Well don't worry, as we'll explain how to choose a card and recommend the ones you should buy for each type of device.
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MicroSD card buying guide
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.
A new 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.
It can be confusing to choose a card as there are so many standards and logos. Some markings refer to speed, others to capacity. Here's how to figure them out.
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 better. 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.
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. A2 is very new, but A1 cards should be fast enough for running apps and games.
So which 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!
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.
1. Samsung Evo Plus
Samsung is one of the biggest brands, so you're likely to sway towards buying a Samsung-branded microSD card, especially if you have a Samsung phone. The Evo Plus is now the entry-level range, with the Pro Plus and Pro Endurance being more expensive.
We tested the 128GB card, but it's also available in 32GB/64GB/256GB capacities.
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: it scored 10.5 MB/s when reading and 4.7 MB/s when writing.
This makes it one of the best choices overall, especially if you're sticking it in a phone that's capable of recording 4K video.
You can buy microSD cards that work out cheaper per gigabyte, but the Samsung Evo Plus offers the sweet spot where you get great performance at a great price.
2. SanDisk Ultra
If you don't fancy going for SanDisk's top tier cards, its Ultra range also offers solid performance for much lower prices per GB - along with the option of stepping up to a capacious 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.
3. SanDisk Extreme PRO
The fastest microSD card that SanDisk offers for consumer electronics, the Extreme PRO starts at 32GB and goes up to 512GB.
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).
4. SanDisk Extreme Plus
The Extreme Plus is a step down from the Extreme PRO range of microSD cards, and it certainly doesn't disappoint. It claims up to 95MB/s read speeds and 90MB/s write. It's rated both A1 and V30.
We were impressed when we saw it return over 87MB/s and 85MB/s for reading and writing in CrystalDiskMark. 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 a superb choice 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 a fantastic microSD card that's only held back by its high price per GB. Unless you need these high speeds, you'll find better value elsewhere.
5. Toshiba Exceria M303E
The M303E is Toshiba's endurance model, which is what the E stands for. It's designed for use in dash cams in particular where it can survive the vast range of temperatures these devices experience, and can also handle continuous video recording - which also makes it a solid choice for a drone or security camera that can record to microSD.
Toshiba says the 128GB card will stand up to 6000 hours of Full HD recording, while the 32- and 64GB models will handle up to 3000 hours.
All three cards meet the V30 standard for recording 4K video and also the A1 standard for use in phones and tablets.
In our tests, the M303E fell a little short of the 'up to 98MB/s' read speed claim, but is still more than fast enough at 87.7MB/s. Impressively, it performed much better than the stated 65MB/s write speed: our 128GB test card managed over 70MB/s in Crystal Disk Mark.
Regardless of any of this, the main issue with the card is availability. Although it was launched earlier this year, it's still hard to find on sale and we could only find it on ebay from a French seller.
Many modern phones have a microSD slot that allows you to add up to 2TB of storage. However, that’s academic since the largest cards until now have been limited to 256GB in capacity.
Integral is the first company to break through that barrier and its latest card offers double the storage at 512GB. That’s still a mere quarter of the 2TB limit, but it’s still a considerable amount of storage when even the largest-capacity phones top out at 128GB.
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: it’s rated as V10, the lowest of the new video recording standards. In our tests, we found it managed a sustained write speed of 19.3MB/s. That’s plenty for Full HD 1920x1080 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 puts on an impressive show with 7.3MB/s for reading and 1.7MB/s for writing.
When you calculate the cost per GB, it’s not as cheap as you might hope for (though the smaller capacity cards are much better value), but if you need this much storage, it’s currently your only option.
7. Toshiba M203 microSD
At face value, the Toshiba M203 is one of the best microSD cards around with everything going for it. The card is water-resistant, shock-proof and comes in five different capacities: 16-256GB at low prices.
Even at 256GB, the M203 is just 16p per GB. So if you're looking for value for money then you've found it. Some of the other capacities are even cheaper per GB.
The M203 is also Class 10/UHS 1 so offers speeds of up to 100MB/s designed for both cameras and phones. In our tests we found the M203 the fastest card at a whopping 99.6MB/s, few MB/s clear of rivals in sequential read.
So what's not to like? Well the card doesn't have great sequential write speeds, just 17.7MB/s, but this is why it's cheaper.
This means it's only fast enough for Full HD (1080p) video recording so if you need 4K then look to the Toshiba Exceria M302 which is only £10 more comparing the 256GB models.
Although it's made for phones, the 4KB performance isn't as good as rivals with a read speed of 8.6MB/s. That's not too shabby but 0.7MB/s write speed is slow, almost the slowest of the lot.
8. Transcend Ultimate microSD
Transcend's Ultimate range offers good performance and a lifetime warranty, and also uses MLC technology.
It's not cheap: £40 for at 64GB card makes it one of the most expensive here at over 60p per GB. The 32GB version works out cheaper per GB, but only marginally.
The good news is that it almost matched the SanDisk Extreme Plus for sequential read and write speeds: 85.8MB/s and 82.8MB/s respectively.
It couldn't keep up in the 4KB tests, though, averaging 8MB/s when reading and 1.5MB/s for writing. That's quicker than average, but the cheap-as-chips Samsung Evo outperforms it for phone and tablet use.
The Transcend Ultimate is really only a sensible choice if you need the fastest write speeds for high-bitrate 4K recording, where it almost matches the SanDisk card, but at a cheaper price. It's much better value in the US, where the 64GB card costs less than $20.
9. PNY Turbo Performance microSD
PNY’s Turbo Performance microSD card is designed for 4K action cams (or drones) with a claimed 90MB/s speed, although as we found out during our testing, this refers to read speeds rather than write speeds.
Using CrystalDiskMark, we saw fairly decent results with 90.4MB/s read speeds and 62.2MB/s write speeds. The latter is more than enough for recording 4K in consumer cameras, but it's not the fastest we've seen.
But what about for use in smartphones and tablets? With a focus on action cameras, it’s not surprising that its random 4KB performance wasn’t the greatest with read speeds of 7.1MB/s and write speeds of only 0.6MB/s. So don't buy it with a view to sharing it between your action camera and an Android phone.
In terms of price, the 32GB version is £19.99 from Amazon, which is a decent 16p per GB.