Types of SD Cards Explained: SD, SDHC, SDXC, SDUC

If you’re shopping for memory cards, you’re bound to come across labels like SD, SDHC, SDXC, and SDUC. These names can look confusing at first, but they mainly describe the card’s storage capacity standard.

The four main types of SD cards are SD, SDHC, SDXC, and SDUC. SD supports up to 2GB, SDHC supports over 2GB to 32GB, SDXC supports over 32GB to 2TB, and SDUC supports over 2TB to 128TB.

This guide explains the different types of SD cards, how they compare, what file systems they use, and how to choose the right card type for your device or application.

SD Card Types Comparison Chart

SD Card Type	Capacity Range	File System	Common Use
SD	Up to 2GB	FAT12 / FAT16	Older cameras, legacy devices, basic storage
SDHC	Over 2GB to 32GB	FAT32	Digital cameras, handheld devices, HD video, industrial equipment
SDXC	Over 32GB to 2TB	exFAT	4K video, drones, gaming, embedded systems, high-capacity storage
SDUC	Over 2TB to 128TB	exFAT	Future high-capacity storage applications

Capacity ranges are based on SD Association SD, SDHC, SDXC, and SDUC standards.

What Are the Different Types of SD Cards?

There are four main SD card capacity formats you’ll encounter:

• SD: Secure Digital
• SDHC: Secure Digital High Capacity
• SDXC: Secure Digital Extended Capacity
• SDUC: Secure Digital Ultra Capacity

Each SD card type has its own capacity range, file system, and device compatibility. Understanding these differences is important when comparing SD vs SDHC vs SDXC vs SDUC cards.

1. SD Cards

• Capacity: Up to 2GB
• File System: FAT12 / FAT16
• Introduced: 1999

SD cards were the original Secure Digital card format. They support lower storage capacities and are now mostly used with older devices or legacy equipment that was designed before newer SD card standards became common.

Compatibility: Standard SD cards work best with older devices that specifically support SD cards. Many modern devices are designed around SDHC or SDXC cards instead.

2. SDHC Cards

• Capacity: Over 2GB to 32GB
• File System: FAT32
• Introduced: 2006

SDHC cards expanded storage capacity beyond the original SD format. They are commonly used in cameras, handheld devices, industrial equipment, and applications that need more storage than a standard SD card can provide.

Because SDHC cards commonly use FAT32, they are widely supported, but individual file sizes may be limited compared to exFAT-based SDXC cards.

Compatibility: SDHC cards require SDHC-compatible or newer devices. Devices that only support the original SD format may not read SDHC cards.

3. SDXC Cards

• Capacity: Over 32GB to 2TB
• File System: exFAT
• Introduced: 2009

SDXC cards are one of the most common options for modern high-capacity storage. They are often used for 4K video, high-resolution photography, drones, action cameras, gaming devices, embedded systems, and commercial applications.

SDXC cards use the exFAT file system, which supports larger files and makes them better suited for video recording and high-capacity storage compared to older SDHC cards.

Compatibility: SDXC cards require SDXC-compatible or SDUC-compatible devices. They may not work correctly in devices that only support SD or SDHC.

4. SDUC Cards

• Capacity: Over 2TB to 128TB
• File System: exFAT
• Introduced: 2018

SDUC cards represent the highest-capacity SD card standard. They are designed for future storage applications that require extremely large capacities, such as advanced video production, high-resolution imaging, extended recording, and next-generation data storage.

Compatibility: SDUC cards require SDUC-compatible hardware. Many current devices do not support SDUC yet, so always check the device specifications before choosing this format.

SDHC vs SDXC vs SDUC: Key Differences

The biggest difference between SDHC, SDXC, and SDUC is capacity. SDHC supports over 2GB to 32GB, SDXC supports over 32GB to 2TB, and SDUC supports over 2TB to 128TB.

SDHC cards commonly use FAT32, while SDXC and SDUC cards use exFAT. For basic photography, device storage, or lower-capacity applications, SDHC may be enough. For 4K video, larger files, drones, cameras, and modern embedded systems, SDXC is usually the better fit. SDUC is intended for future high-capacity storage needs.

SD Card Types vs SD Card Sizes

SD, SDHC, SDXC, and SDUC refer to storage capacity standards. Full-size SD and microSD refer to the physical size of the card.

For example, a 128GB microSD card is usually a microSDXC card because it uses the microSD physical size but falls within the SDXC capacity range. This is why it is important to check both the card type and the device’s supported form factor.

How to Choose the Right SD Card Type

When choosing the right SD card type, look at your device requirements first. The wrong card type may not work, even if the card physically fits into the slot.

1. Check Device Compatibility

Check your device manual or product specifications to confirm which SD card types it supports. You cannot use SDXC or SDUC cards in devices that only support SDHC.

2. Match the Capacity to the Application

• Up to 2GB: Older devices, legacy equipment, basic storage
• Over 2GB to 32GB: SDHC cards for cameras, handheld devices, HD video, and general storage
• Over 32GB to 2TB: SDXC cards for 4K video, drones, action cameras, embedded storage, and larger files
• Over 2TB: SDUC cards for future high-capacity applications

3. Review Speed Requirements

After choosing the correct SD card type, check the speed rating. Ratings such as Class 10, U1, U3, V30, V60, and V90 help indicate whether the card is suitable for video recording, photography, or continuous write applications.

4. Consider Operating Environment

For industrial, embedded, transportation, security, or field equipment, standard consumer cards may not be enough. Applications exposed to temperature changes, vibration, long service cycles, or continuous writes may require industrial or application-specific flash memory cards.

Choosing SD and microSD Cards for Industrial Applications

Industrial and embedded systems often need more than basic capacity. Depending on the application, buyers may need to consider temperature grade, flash type, endurance, lifecycle support, and long-term availability.

AMP supports SD and microSD flash memory sourcing for industrial, commercial, embedded, and application-specific systems. If you need a specific capacity, speed rating, temperature grade, or product option, AMP can help review availability and alternatives.

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Frequently Asked Questions About SD Card Types

Last updated: July 2026. Reviewed by AMP Inc.’s memory and storage team.