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A man using a laptop in the floor with a drone, DSLR, and action cam nearby

How to select the right memory card for your use

The important factors in choosing a memory card are speed, capacity and the type of device you’re using it in. Having the most capacity at an affordable price is ideal, but it’s also important to have a memory card that has a fast enough write speed to capture all your footage without any errors. Depending on your needs and usage, you’ll want to think about choosing the memory card with the correct format.

Megabits vs megabytes

The first aspect that may cause confusion is the difference between megabits and megabytes. MB/s means megabytes per second while Mb/s means megabits per second. At times, they’re also written as “MBps” and “Mbps”, as if the difference between the two wasn’t already confusing enough.

To put it more simply, get rid of the “mega” and just focus on bits and bytes. 1 byte is made up of 8 bits. So 1MB/s = 8Mb/s. This is important because some camera manufacturers will indicate their cameras’ video data rates in megabits rather than megabytes.

For example, Sony’s a7S III mirrorless camera has a 4K video data rate of 600 megabits per second (Mb/s). If you were looking for an SD card to use in the a7S III, you might think that you need a memory card with a sustained write speed of 600 megabytes per second (MB/s) when really the video data rate is referring to the speed in bits rather than bytes.

To determine what the video data rate is in megabytes, some simple math is required to calculate the conversion from bits to bytes. Since 1 byte is made up of 8 bits, simply take the number of bits and divide it by 8. 600 divided by 8 is 75 meaning 600Mb/s is really 75MB/s which is a lot slower than you initially thought. In the end, you would need an SD card that can sustain a minimum write speed of 90MB/s.


DSLR with an SD card on desk

For photography, some users prefer several smaller cards to a single large one to minimise the risk of losing all their photos if a card corrupts. If you’re shooting in RAW format where files might be 50MB or more, you’ll benefit from having U1 or U3 speeds.

Many DSLR and mirrorless cameras can shoot in burst mode which means that you can capture many images consecutively by holding the shutter button down. All those frames are first temporarily stored in the camera’s internal memory, called the buffer. The camera then writes the data from the photos stored in the buffer onto the memory card. The camera needs to transfer this data quickly and efficiently, especially if it’s shooting in burst mode, which is why having a fast memory card is important for optimal performance. The card needs a fast write speed to keep the buffer from jamming up and bottlenecking the data transfer.

Be sure to check your camera’s specs for the recommended speed class.

4K video

Landscape image in 4K

The SD Card Association recommends UHS Speed Class 3 (U3) or better for shooting 4K video, but a Video Speed Class of V30 or more is ideal since newer cameras today record 4K resolution at 120fps (frames per second). It’s better to have a faster memory card for recording video for a camera that shoots with a higher number of frames per second.

Higher-rated speed class cards support high bitrates of video and higher quality video recordings, but one thing to keep in mind is that your camera must be able to handle the card’s speed. There’s no point in purchasing a higher-rated speed class card if your camera can’t support the card’s write speed. In most cases, you can put a very fast card in a slower camera and still make it work but you won’t fully benefit from the highest speeds that the card is capable of.

Check your camera’s specs for the recommended speed class and see if you need to go beyond the requirement depending on the video resolution and the number of frames per second that you’re shooting. Learn more about choosing storage for shooting 4K video.


Inserting a Kingston microSD card into a drone

Drones typically use microSD cards to store all their footage. You’ll want to get a few large capacity microSD cards that can handle fast throughput for resolutions like 4K video.

Check with your device manufacturer to see what capacity and speed class is recommended for your drone. Each drone has different requirements depending on the manufacturer and brand. For example, the DJI Mavic Air 2 has a max capacity of 256GB and can record in 4K resolution at write speeds of up to 120Mb/s or 15MB/s. You’ll want a card with 32GB, 64GB, 128GB or 256GB capacity with a speed class of U3 or V30.

We recommend having multiple microSD cards for your drone to reduce the chances of losing footage since memory cards do wear out over time. You never know what could happen out in the field, and having all your footage on one card poses a risk of losing your footage all at once. Learn more about choosing storage for drones.


microSD card being inserted into a GoPro

GoPro has a list of recommended microSD cards on its website. The website states that all GoPro cameras require a minimum of Class 10 microSD cards, but it’s better to consider a speed class of U1 or U3 since they have better specs in terms of speed, which allows you to fully maximise the potential of your GoPro. GoPro camera card support:

  • The HERO (2014) supports up to 32GB
  • HERO3 Black, HERO3+, HERO+ and HERO+ LCD support up to 64GB
  • HERO4, HERO Session, HERO Fusion, HERO5 Black, HERO6 Black, HERO (2018), HERO7 Silver & White support up to 128GB.
  • HERO7 Black, HERO MAX and HERO8 Black support up to 256GB.

If you’re shooting 4K videos with your GoPro, you’ll want to consider a microSD card with a high speed class. Shooting a GoPro video in 4K at 60fps with a write speed of 12MB/s requires a fast microSD card with at least a U3 or V30-rated speed class. It’s a highly demanding task that requires a fast write speed with plenty of storage. Even shooting 1080p at 240fps is demanding enough to require a fast memory card with a large capacity.

Check your GoPro’s specifications to see which microSD card is compatible and whether you need to go beyond the minimum requirement in terms of speed and capacity. Learn more about choosing storage for a GoPro.

Nintendo Switch and 3DS

Nintendo Switch and microSD card

The Nintendo Switch accepts microSDXC cards with up to 2TB of storage, which is great if you download your games. We recommend getting a high-capacity memory card for your Switch since games take up a ton of storage. If you’re downloading games like “Legend of Zelda: Breath of the Wild”, which takes up to 13.4GB, you’re going to need a high-capacity memory card to expand the 32GB of storage that already comes with the Nintendo Switch.

Conversely, microSDXC cards aren’t available for Nintendo 3DS, 3DS XL and 2DS owners. The Nintendo 3DS/2DS only supports SDHC cards with 32GB or less. You’ll just have to purchase several 32GB microSD cards if you plan on downloading many games. Learn more about choosing storage for Nintendo Switch.

Android™ Phones

If you’re planning on shooting 4K videos on your phone, you’ll need a microSDXC card with a speed class of U3 and at least 64GB of storage. If not, a 16GB or 32GB microSDHC card is fine for most smartphone users to store photos, videos and mobile games. A 32GB microSDHC card should last for a while before running out of storage space. Many smartphones, including the Samsung Galaxy S20 and LG G8, support microSDXC cards with up to 1TB of storage. Learn more about choosing storage for Android phones.


For those who want to record driving footage on a dashcam, the most important factors to consider are the amount that you will be driving and the conditions your car will endure. For both of these, a high-endurance card is essential. High-endurance microSD cards stand up to both repeated writes and rewrites, and extremes of temperature that you might encounter while driving or while your car is at rest. Ideally, the card you choose will be protected against extremes of temperature, shock and water. Learn more about choosing storage for dashcams. Learn more about choosing storage for dashcams.

Security cameras

A white security camera sitting between a candle cup and a potted cactus

When selecting a storage card for use in security cameras, you will need to take into account what type of footage the camera is recording: is it low resolution or high? The difference between 720p footage file size and 1080p is substantial, and the difference between 1080p and 4K file size is even larger. Will the camera only record after detecting motion, or around the clock? Write speed is essential for your purposes here. A slow write speed could mean that your camera’s footage is choppy or distorted because of the storage format’s inability to keep up with what is being recorded.
Especially when considering exterior security cameras, storage cards should be durable and resilient against the elements and variances in temperature. Learn more about choosing storage for security cameras.


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