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An SD card’s “format” can mean its capacity class, its usual file system, or the act of formatting it. The card’s SD, SDHC, SDXC or SDUC marking identifies its capacity class; that class is paired with a typical file system, but it does not guarantee that a particular device can use the card. Check the host device’s supported SD standard and manual before buying or formatting.
What does “SD card format” mean?
The phrase has three common meanings:
- Capacity class: SD, SDHC, SDXC or SDUC, identified by the card’s label or logo.
- File system: the way files are organized on the card. SD standards pair each capacity class with a usual file system.
- Formatting: the process of preparing or erasing a card’s file system. Formatting does not change the card’s capacity class.
The class-to-file-system pairings below come from the SD Association’s capacity overview. They describe the standard pairing, not universal compatibility with every camera, phone, computer or card reader.
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Which file system does each SD card class use?
| Card class | Capacity range | Usual file system |
|---|---|---|
| SD | Up to 2 GB | FAT 12/16 |
| SDHC | More than 2 GB through 32 GB | FAT32 |
| SDXC | More than 32 GB through 2 TB | exFAT |
| SDUC | More than 2 TB through 128 TB | exFAT |
These are capacity-standard ranges published by the SD Association; the pages do not state a publication year. SD, SDHC, SDXC and SDUC are different standards, not just different names for a file system. Reformatting an SDXC card as FAT32, for example, does not turn it into an SDHC card.
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Will a card work in your device?
Compatibility depends on the SD standard supported by the host device. The SD Association’s guidance describes backward compatibility: a newer-generation host supports cards from earlier generations, but an older host does not thereby gain support for a newer card class.
#1 Best Overall
- 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.)
| Host device standard | Card classes supported |
|---|---|
| SD | SD |
| SDHC | SD, SDHC |
| SDXC | SD, SDHC, SDXC |
| SDUC | SD, SDHC, SDXC, SDUC |
Use the device’s SD logo, specifications or manual to confirm its supported card standards and maximum capacity. An SDHC-only device does not support an SDXC card simply because the card has been reformatted. The SD Association’s capacity-choice guidance and FAQ explain the compatibility generations; the manual is the best source for the exact limits of your device.
Capacity is not speed
Capacity class and file system do not tell you how quickly a card can sustain recording. Speed classes describe minimum sequential access performance under conditions defined by the standard. They matter particularly for video recording and other sustained-write work, and are separate from SD/SDHC/SDXC/SDUC capacity classes. Check your device manual for the speed class it recommends for your workload. The SD Association outlines the categories in its speed class guide for video recording.
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.
How to identify and prepare your card
- Read the card marking. Find the SD, SDHC, SDXC or SDUC logo and note the stated capacity.
- Check the host device. Look for its SD standard marking or consult the manufacturer’s specifications or manual. Confirm both supported card class and maximum capacity.
- Check speed requirements. If you record video or perform another sustained-write task, follow the manual’s recommended speed class.
- Back up files before formatting. Formatting is destructive and can erase the card’s contents.
- Follow the device maker’s formatting instructions. The SD Association recommends using its SD Memory Card Formatter rather than general operating-system formatting utilities, noting that generic utilities may produce less-than-optimal performance. Its consumer guidance describes the formatter as created for SD, SDHC and SDXC cards; check current platform-specific software documentation for supported operating systems and cards. Also confirm that your card-interface device is compatible with the card before using the utility.
For more detail on the formatter, see the SD Association’s user manual. Formatting is not a compatibility workaround: a device that does not support a card’s SD generation should not be assumed to support it after the file system is changed.
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Best Value
- Great choice for compact to mid-range point-and-shoot cameras
- Quick transfer speeds up to 140MB/s (Up to 140MB/s read speed engineered with proprietary technology to reach speeds beyond UHS-I 104MB/s, requires compatible devices capable of reaching such speeds. Based on internal testing; performance may be lower depending on host device, interface, usage conditions and other factors. 1MB=1,000,000 bytes.)
- Up to 128GB to store tons of pictures (1GB=1,000,000,000 bytes. Actual user storage less.)
- Exceptional video recording performance with UHS Speed Class 1 (U1) Class 10 rating for Full HD video (1080p) (UHS Speed Class 1 (U1) designates a performance option designed to support real time video recording with UHS enabled host devices. See consumers speed page on SanDisk site. Full HD (1920x1080) video support may vary based upon host device, file attributes, and other factors. Visit the SanDisk Video Knowledge Base for more information.)
- Compatible with SanDisk SD UHS-I card reader (sold separately)
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
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 90MB/s (Write speed up to 90MB/s. Based on internal testing; performance may be lower depending upon host device. 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.)
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