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Clear out junk files and repair common Windows errorsFree Scan →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →“SD card size” can mean two different things: the card’s physical shape, which determines whether it fits a slot, or its storage capacity, which determines how much it can hold. A third label—speed class—matters when a device must write data continuously, such as while recording video. Check all three against your device before buying.
What does SD-card size mean?
Physical size and storage capacity are separate specifications. Full-size SD cards measure 32 × 24 × 2.1 mm; microSD cards measure 11 × 15 × 1.0 mm. Full-size SD uses nine pins and microSD uses eight. MiniSD is a legacy format that the SD Association says has largely been replaced by microSD. SD Association: SD standards
Capacity labels—SD, SDHC, SDXC and SDUC—identify standards and capacity ranges, not different physical dimensions. A card can therefore be the right shape but the wrong standard or capacity for a device.
Which capacity family do you need?
| Card family | Capacity range | File system listed by the SD Association |
|---|---|---|
| SD | Up to 2GB | FAT12/16 |
| SDHC | Over 2GB to 32GB | FAT32 |
| SDXC | Over 32GB to 2TB | exFAT |
| SDUC | Over 2TB to 128TB | exFAT |
These are the SD Association’s capacity ranges and associated file systems. SD Association: capacity standards A 256GB card, for example, falls in the SDXC family; that label alone does not establish whether a particular camera, computer or other device supports it.
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#1 Best Overall
Will a card work in your device?
Compatibility depends on the host device, not simply on whether the card looks newer or has more capacity. The SD Association advises: “Before inserting your SD memory card, confirm the device is compatible with the SD standard by locating an SD logo and other symbols on the device or referring to the device’s user manual or manufacturer information.” SD Association: consumer compatibility guidance
| Host device standard | Card families it accepts |
|---|---|
| SD | SD only |
| SDHC | SD and SDHC |
| SDXC | SD, SDHC and SDXC |
| SDUC | SDUC required |
This interoperability guidance means an SDHC host does not support an SDXC card, even though the card may physically fit. Check the device manual or manufacturer specifications for both the supported capacity family and the physical slot type.
Rank #2
- CAPTURE LARGER THAN LIFE. Unlock 4K UHD(3) brilliance and pristine high res stills with video speed class ratings of U3 and V30(4).
- SPEED BARRIERS SHATTERED. Save precious moments with blazing read speeds up to 250MB/s(2) and write speeds up to 170MB/s(2) [256GB-1TB capacities(1)].
- MAXIMIZE WITH MASSIVE CAPACITY. Capture for longer and store more with up to 2TB(1) of storage that can hold up to 2,808 minutes of 4K UHD video recorded at 30 fps (641MB/minute)(9).
- DEFY THE ELEMENTS. Unrelentingly resilient, Sandisk SD memory cards are engineered to perform in extreme conditions, despite rough handling and constant use.(6)
- CONTENT MANAGEMENT, SIMPLIFIED. Back up, organize, and transfer everything easily with the Sandisk Memory Zone desktop app,(7) whether you use an SD card slot or a card reader.
Does a microSD card fit an SD slot?
A microSD card is smaller than a full-size SD slot and does not fit it directly. A suitable SD adapter can let a microSD card sit in a full-size SD slot, but the adapter does not change the card’s capacity family, speed capability or the host’s compatibility requirements. Confirm that the device supports the card standard as well as the adapter’s form factor.
Which SD-card speed class is right for video?
For sustained recording, look first at the minimum speed class required by the device. The SD Association identifies four class families: Speed Class, UHS Speed Class, Video Speed Class and SD Express Speed Class. These classes specify minimum sequential performance under defined conditions, making them more useful for workloads such as continuous video writing than an advertised peak read speed. SD Association: speed classes
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Rank #3
- Save time with card offload speeds of up to 200MB/s powered by SanDisk QuickFlow Technology (Up to 200MB/s read speeds, engineered with proprietary technology to reach speeds beyond UHS-I 104MB/s, require compatible devices capable of reaching such speeds. Based on internal testing; performance may be lower depending upon host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes. X = 150KB/sec. SanDisk QuickFlow Technology is only available for 64GB, 128GB, 256GB, 512GB and 1TB capacities. 1GB=1,000,000,000 bytes. 1TB=1,000,000,000,000 bytes. Actual user storage less.)
- Pair with the SanDisk Professional PRO-READER SD and microSD to achieve maximum speeds (sold separately)
- Shot speeds up to 140MB/s (Write speed up to 140MB/s. Based on internal testing; performance may be lower depending upon host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes. X = 150KB/sec.)
- Perfect for shooting 4K UHD video and sequential burst mode photography (Full HD (1920x1080) and 4K UHD (3840 x 2160) video support may vary based upon host device, file attributes and other factors. See HD page on SanDisk site.)
- UHS Speed Class 3 (U3) and Video Speed Class 30 (V30) (UHS Speed Class 3 designates a performance option designed to support 4K UHD video recording with enabled UHS host devices. UHS Video Speed Class 30 (V30), sustained video capture rate of 30MB/s, designates a performance option designed to support real-time video recording with UHS enabled host devices. See the SD Association’s official website.)
Match the class printed on the card to the host’s requirement. If the host requires UHS Speed Class 1, the SD Association says a UHS Speed Class 1 or UHS Speed Class 3 card can be used. SD Association: speed-class guidance Follow the camera or device maker’s stated requirements for the recording mode you plan to use; the label “4K” alone does not specify a universal card class.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.What do UHS-I, UHS-II and other bus labels mean?
Bus labels describe the interface’s published speed ceiling, not a guaranteed transfer rate for every card and device. The SD Association gives these figures: SD Association: bus-speed guidance
Rank #4
- Fast for better pictures and Full HD video. Full HD (1920x1080) video support may vary based upon host device, file attributes, and other factors
- Great choice for compact to mid-range point-and-shoot cameras
- From 32GB to 256GB(1) to store tons of pictures and even more Full HD video(2). (1)1GB=1,000,000,000 bytes Actual user storage less
- Exceptional video recording performance with UHS Speed Class 1 (U1)(5) and Class 10 rating for Full HD video (1080p)(2). (5)UHS Speed Class 1 (U1) designates a performance option to support real time video recording with UHS enabled host devices
- Quick transfer speeds up to 100MB/s. Up to 100MB/s[64GB-256GB; 90MB/s for 32GB] read speed; write speed lower Based on internal testing; performance may be lower depending on host device, usage conditions, and other factors 1MB=1,000,000 bytes
| Bus interface | Published figure |
|---|---|
| Default Speed | 12.5 MB/s |
| High Speed | 25 MB/s |
| UHS-I | Up to 104 MB/s |
| UHS-II | 156 MB/s full duplex; 312 MB/s half duplex |
| UHS-III | 624 MB/s full duplex |
| SD Express | Up to 3940 MB/s |
These are interface figures, not promises about an individual card’s actual performance. The SD Association notes that transfer speed varies with the card, host, operation and stored data. A fast bus label also cannot compensate for a card that fails to meet the device’s required minimum write class.
Quick Recap
Best Value
- EXPAND YOUR STORAGE. Insert your card to add massive storage up to 1.5TB[1] to your Android smartphones and tablets, digital cameras, and laptops.
- SPACE FOR MORE. With expansive capacities up to 1.5TB[1], capture and store hours of Full HD video[4], movies, music, games, photos, and podcasts.
- MOVE FILES FAST. Use your card with the SANDISK QuickFlow microSD UHS-I Card USB-A Reader[6] to achieve up to 195MB/s[2] read speeds [128GB-1.5TB models] and offload your content fast.
- LOAD APPS IN A SNAP. Rated A1[3], the SANDISK Ultra microSD card is optimized for faster app launch and overall app performance.
- EASY CONTENT MANAGEMENT. Easily back up, organize, and transfer your photos and videos with the SANDISK Memory Zone desktop or Android mobile app[5].
How to choose an SD card
- Check the slot. Determine whether your device takes full-size SD or microSD; consult its manual if the slot or symbols are unclear.
- Check supported card families. Find the device’s maximum supported SD standard or capacity. Do not assume an SDXC or SDUC card works just because it fits.
- Match the required speed class. For video or other sustained writes, meet the minimum class specified for the device and recording mode.
- Consider the bus interface. Choose a compatible interface if transfer speed matters, but treat its published ceiling as a limit rather than a guaranteed card speed.
- Choose capacity within the supported family. For instance, a 256GB card is SDXC; buy it only if the device supports SDXC and the required physical format.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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