No other card we considered combines this amount of storage with these speeds, as high as 285 Mbps. Compatible with virtually every modern device. 256 GB model lets you shoot a lot of video and images without needing to change cards.
May be impractical for occasional users. Incompatible with many older devices.
Durability sets it apart; both shockproof and waterproof, and won't be damaged by airport security equipment. Compatible with most modern digital and action cameras. 80 Mbps transfer speed compares favorably with most other SD memory cards.
Slightly slower write speed. May lag or buffer when recording 4K video.
Above average speeds with up to 300x write speeds, 90 Mbps transfer. Plug-and-play formatting and self-correcting transfer error technology make it easy to use. Especially good option for use with older and newer devices.
Some reports of write and transfer speeds getting slower with frequent use.
Up to 512 GB of storage; good option for storing a lot of photos or video. 4K and 1080p capture capabilities for clear, vivid shots. 95 Mbps transfer speeds among highest of any card we considered except ultra-high-speed models. Compatible with most devices, even most older cameras.
Doesn't include travel case. Durability may be an issue.
Write speeds up to 299 Mbps; transfer speeds up to 300 Mbps for clear, continuous capture of 4K video. Designed for modern digital and action cameras; compatible with almost all brands and models with SD card readers. Available in storage capacities up to 128 GB.
May not be compatible with many older models.
We purchase every product we review with our own funds — we never accept anything from product manufacturers.
Secure Digital (SD) memory cards are the unsung heroes of the electronics world. They store our files so we can make the most of our favorite gadgets – whether that’s the latest images from our digital cameras, home movies from our smartphones, or even our favorite games for portable gaming devices.
And while it’s hard to get excited about buying system memory, it’s a crucial thing to get right. That’s because the wrong SD memory card could end up slowing down your device or, worse, be entirely incompatible. With so many SD memory cards on the market, choosing one with the right balance of performance and storage can seem overwhelming.
At BestReviews, we’re here to help. With our top picks and information-packed shopping guides, it’s easy to find the best products for your home. If you’re ready to buy your first SD memory card, or if you’re just looking to beef up the memory in your favorite tech toy, keep reading.
Most SD memory cards look the same on the outside, so knowing the technical terms and acronyms is especially important for understanding the differences between various models. SD memory cards come in three main varieties: SD, SDHC, and SDXC.
SD memory cards
SD memory cards are the original format of SD memory, and they come in storage amounts up to 2GB of data. SD cards are the slowest memory cards available, but they are compatible with all card readers.
SDHC memory cards
Secure Digital High Capacity (SDHC) memory cards are like SD cards, but they transfer data faster and come in capacities up to 32GB. SDHC memory cards aren’t compatible with SD card-only readers, but that’s not as bad as it sounds – most modern card readers handle SDHC without a problem.
SDXC memory cards
Secure Digital Extended Capacity (SDXC) memory cards offer an even bigger bump in terms of both performance and storage. SDXC memory cards come in sizes ranging from 32GB to 2TB. Like SDHC memory cards, SDXC memory cards require a compatible reader.
If you’re not sure which type of SD memory card to get, think about the device you’ll be using your memory card with. If you plan on using it with a device that requires a lot of storage capacity (like a 4K video camera), you’ll probably need an SDHC or SDXC memory card. If all else fails, consult the device’s documentation. Manufacturers typically include information about which types of SD memory cards will work best.
Some smartphones use microSD memory, which requires a specific type of SD memory card. MicroSD cards function identically to normal SD memory cards, but they’re much smaller. A microSD card can be used with an SD memory card adapter, which allows it to work with standard SD memory card ports and accessories.
If you interact with SD memory cards a lot, the right accessories can make a big difference. Here are the extras we recommend picking up when you buy an SD memory card.
Memory card case
Many photographers buy several SD memory cards, and then cycle through them on a regular basis. If you’ve got more than a handful of SD memory cards, an organizing case can help make sure none get lost, and the ones you need most are always accessible.
USB card reader
If your computer doesn’t have a built-in SD memory card reader, then getting one is essential – you won’t be able to transfer your files without it. Most USB card readers have multiple ports, so buying one has the added bonus of expanding your computer’s connectivity options.
Smartphone memory card adapter
If you’ll be using your SD memory card to make copies of the photos on your phone, you’ll need a smartphone memory card adapter. Just make sure the one you buy is compatible with your phone’s USB port.
Some SD memory cards have built-in WiFi, so you can manage content without having to physically remove the card. Wireless SD memory cards are definitely some of the priciest around, but if you prefer convenience (or you lose SD memory cards a lot), a wireless card is a sound investment.
In general, SD memory cards don’t cost a lot, but it’s still important to know how to spot the difference between a bargain and a gimmick. Here’s what to expect price-wise.
$10 to $29
In this price range, you’ll find SD memory cards that look like bargains, but typically aren’t. These SD memory cards are usually short on either storage or performance. If you need an SD memory card in a short-term situation, you can find an adequate budget model. But if you want a fast card with plenty of room, you’ll need to spend a little more.
$30 to $99
These cards are the best bargains in SD memory cards. In this price range, you’ll want to consider your priorities. If you want a fast card with a moderate amount of storage, look on the lower end, but if you need a card with a lot of space, you should expect to spend closer to the $100 mark.
$100 to $250
At the high end, you’ll encounter SD memory cards with massive amounts of storage, blazing speeds, and innovative features like built-in WiFi. If you need SD memory cards for professional use, these are the cards you should look at.
If you own an iPhone, buying a lightning to SD card adapter can be a great way to get your photos off your phone and onto a memory card. Even if you want to keep copies of your photos on your iPhone, having copies of them on a memory card is a convenient backup option.
As you’re comparing different SD memory cards, keep these tips in mind.
If you’re buying an SD memory card for a digital camera, find out the average file size for the camera’s highest-resolution photographs. The better the camera, the larger the photo files will be, so make sure to get an SD memory card with the right amount of storage. Take a photo with your camera, then examine the file size. With that number in mind, you can start to calculate how much storage you’ll need for hundreds, or even thousands, of photos.
Buy more capacity than you think you’ll need. No matter what the device, SD memory card storage always goes faster than you think. Avoid running out of space at a crucial photo op by buying more than you think you’ll need. Most users never complain about having too much storage.
Q. How long can I keep my data on an SD memory card? Do SD memory cards ever deteriorate?
A. Most data will be safe on an SD memory card for up to 10 years from when you first buy the card. However, SD memory cards do degrade over time, so it’s best to make backup copies of your content on an ongoing basis. It’s possible to extend the life of an SD memory card by using a computer to reformat the storage. Reformatting essentially resets the clock on decay, but it also wipes out everything on the card, so you’ll need to perform a backup beforehand.
Q. How do I get data off an SD memory card?
A. To transfer files from an SD memory card to a computer, you’ll need an SD memory card reader. Most laptops have built-in SD memory card readers, so you can simply insert the card, and the operating system will recognize it as local storage. If your computer doesn’t have a built-in reader, you’ll need to buy a USB card reader, which turns any existing USB port into an SD memory card reader.
If you buy a WiFi-enabled SD memory card, follow the manufacturer’s instructions for transferring content from the memory card to a device over your WiFi network.
Q. Is an SD memory card the same thing as an xD-Picture Card?
A. No. An xD-Picture Card is a unique type of memory card that only works in certain Fujifilm and Olympus cameras. If you own a Fujifilm or Olympus camera, check to see if it accepts xD-Picture Cards or standard SD memory cards before buying any additional storage.
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