Quick Answers
SD cards and micro SD cards are both types of removable flash memory cards used for storing data in devices like cameras, phones, and other electronics. The main differences are:
- Size – SD cards are larger, micro SD cards are smaller
- Compatibility – SD is used in larger devices like DSLR cameras, micro SD for smaller devices like phones
- Price – SD cards tend to be more expensive with higher capacities
- Durability – SD cards are generally more durable and reliable
For most uses, micro SD cards are preferable due to their smaller size and wider compatibility. But SD cards are still recommended for uses requiring maximum speed and durability, like high-end cameras.
What are SD and Micro SD Cards?
SD cards and micro SD cards are both types of removable flash memory designed to store photos, videos, music, documents, and other data for use in consumer electronic devices. The main differences between full-size SD cards and micro SD cards are their physical size and intended use cases.
SD Cards
SD cards (Secure Digital cards) are about the size of a postage stamp, measuring 32 x 24 x 2.1 mm. They weigh around 2 grams. The SD standard was introduced in 1999 by the SD Association as a successor to MultiMediaCards (MMC) for use in digital cameras. In addition to cameras, SD cards are commonly used in many consumer devices including:
- Digital cameras
- Camcorders
- Digital audio players
- Cell phones
- Tablets
- Nintendo Switch
- Laptops
- GPS navigation devices
- Drones
- Dash cams
- Home security cameras
SD card capacities range from 1 GB to 1 TB for SDXC cards. The cards use flash memory and have no moving parts, making them more compact and durable than hard drives. Standard SD cards transfer data over an asynchronous interface, with SPI and 1-bit SD modes.
Micro SD Cards
Micro SD cards are a smaller variant of the SD card measuring just 15 x 11 x 1 mm. They weigh under half a gram. The micro SD form factor was created to fit the compact size requirements of small, portable electronics like mobile phones and action cameras. Devices that commonly use micro SD cards include:
- Smartphones
- Tablets
- Action cameras like GoPro
- Drones
- Dash cams
- Digital audio players
- Handheld gaming systems
- Chromebooks
- Smartwatches
Micro SD capacities range from 32 GB up to 1 TB for MicroSDXC. They use the same NAND flash memory as full-size SD cards but in a much smaller physical footprint. Micro SD cards transfer data through a high-speed bus interface capable of up to 104 MB/s read and write speeds with UHS-I compatibility.
Differences Between SD and Micro SD Cards
The main differences between full-size SD cards and micro SD cards come down to their physical size, intended use cases, price points, and some performance factors:
Physical Size
The most obvious difference is physical size. Standard SD cards measure 32 x 24 mm whereas micro SD cards are just 15 x 11 mm. Here is a visual comparison:
| SD Card | Micro SD Card |
|---|---|
| 32 x 24 x 2.1 mm | 15 x 11 x 1 mm |
As you can see, micro SD cards are nearly one third the size of full SD cards. Their tiny size makes micro SD cards ideal for small electronics where space is at a premium, like smartphones. SD cards are better suited to larger devices that have the room to accommodate their bigger physical footprint.
Intended Use Cases
The target use cases differ between the two formats:
- SD cards – Optimized for use in larger cameras and camcorders, laptops, gaming systems, and other devices where both size and performance are important factors.
- Micro SD – Made specifically for small footprint devices like smartphones, action cams, drones, and tablets where compact size is the priority.
For example, most digital SLR and mirrorless cameras still use full-size SD cards because they offer faster transfer speeds and greater reliability for capturing high-resolution photos and 4K video. Meanwhile, smartphones rely on micro SD cards solely due to their tiny size.
Price
The pricing also tends to be different between the two formats. Generally speaking, SD cards have a higher cost per gigabyte compared to micro SD cards. There are a few reasons for this pricing difference:
- Economies of scale – There is higher demand for micro SD cards across consumer electronics, which brings costs down.
- Newer technology – Micro SD utilizes more advanced NAND that brings down the manufacturing costs.
- Higher capacities – SD cards come in larger maximum capacities (up to 1TB currently) which are priced higher.
A 128GB high-end SD card might cost around $40 whereas a 128GB high-speed micro SD card is typically priced closer to $20. However, very high capacity SD cards at 512GB+ can be significantly more expensive than micro SD cards.
Durability and Reliability
The full-size SD card design is inherently a bit more durable and reliable than the miniature micro SD. The larger SD card can dissipate heat better and its slidable write-protect switch minimizes accidental erasures. The connectors used in SD cards tend to be more robust than micro SD as well. Intensive write operations will cause less wear and tear over time with SD cards.
However, both formats still offer decent durability for the average user as long as you handle the cards properly. The extremely compact size of micro SD cards does make them easier to misplace though.
Speed and Performance
SD cards boast faster maximum data transfer speeds compared to micro SD cards. The latest UHS-III SD cards can reach sustained read/write speeds up to 624 MB/s. In comparison, the fastest micro SD cards top out at around 400 MB/s.
But for typical real-world usage in phones and other devices, most users won’t notice much of a difference. Mid-range UHS-I micro SD cards still provide plenty of performance for apps, 4K video, games, and more at around 100 MB/s. Only professional photographers shooting in raw truly benefit from the blazing speeds of high-end SD cards.
One benefit of SD cards is they are more likely to maintain peak read/write speeds during intensive operations like sequential video recording compared to micro SD. So SD remains the preferred format for professional media use.
SD vs Micro SD Compatibility
Due to the significant size difference between formats, SD and micro SD cards are not cross-compatible:
- SD cards – Can only be used in full-size SD slots. Will not fit into a micro SD slot.
- Micro SD – Can only be used in micro SD slots. Needs an adapter to work in full-size SD card slots.
Most devices that support one format will only have slots for that specific type. However, some cameras and mobile devices will include both full-size SD and micro SD slots for flexible storage.
Using Micro SD in Full-Size Slots
It is possible to use micro SD cards in a regular SD card slot by using a simple physical adapter. The adapter converts the micro SD’s form factor to a standard SD card size.
Micro SD adapters are cheap (around $5) and available from any electronics retailer. Simply insert the micro SD into the adapter, then put the adapter into the SD card slot like a normal SD card.
The downside is the adapter adds a small amount of bulk. Also note that while a micro SD card will physically work in a full-size SD slot with an adapter, it may not achieve full performance speeds due to technical limitations.
Using SD Cards in Micro SD Slots
Going the other direction, inserting an SD card into a micro SD slot, is not possible. The SD card is way too large to fit the compact micro SD slot.
There are no adapters to allow using SD in micro SD slots. You have to use a genuine micro SD card designed for that device’s slot.
SD vs. Micro SD Speed Classes
Both SD and micro SD cards are assigned speed classes by the SD Association as a way to indicate guaranteed minimum performance. Speed classes go from Class 2 (slowest) up to Class 10 and UHS I – III (fastest).
Higher speed classes mean the card can sustain higher minimum write speeds, which is useful for recording video or burst photo captures. Here is an overview of the classes:
SD Card Speed Classes
| Class | Minimum Write Speed |
|---|---|
| Class 2 | 2 MB/s |
| Class 4 | 4 MB/s |
| Class 6 | 6 MB/s |
| Class 10 | 10 MB/s |
| UHS Speed Class 1 (U1) | 10 MB/s |
| UHS Speed Class 3 (U3) | 30 MB/s |
Class 10 and UHS-I cards remain the most popular for good performance at affordable prices. Professional SD cards will carry UHS-II or UHS-III ratings for blazing fast speeds.
Micro SD Speed Classes
Micro SD cards use the same speed class ratings as full-size SD cards, indicating the guaranteed minimum write performance:
| Class | Minimum Write Speed |
|---|---|
| Class 2 | 2 MB/s |
| Class 4 | 4 MB/s |
| Class 6 | 6 MB/s |
| Class 10 | 10 MB/s |
| UHS Speed Class 1 (U1) | 10 MB/s |
| UHS Speed Class 3 (U3) | 30 MB/s |
The fastest micro SD cards will carry the U3 or A2 designation for read/write speeds up to 100+ MB/s. This provides speedy performance for recording high-res video, transferring files, gaming, and more. Slow Class 2 cards are best avoided.
Common Capacities
Both SD and micro SD cards are available in a wide range of storage capacities to suit different needs. Here are some of the most common sizes you’ll see:
SD Card Capacities
- 16GB
- 32GB
- 64GB
- 128GB
- 256GB
- 512GB
- 1TB
Higher capacities up to 512GB and 1TB are ideal for holding more photos, videos, games, and apps. 16-64GB cards are good for casual users.
Micro SD Capacities
- 32GB
- 64GB
- 128GB
- 256GB
- 512GB
- 1TB
You’ll most often find 32-128GB micro SD card capacities used in phones, GoPros, drones, and other devices. Larger 256-512GB sizes are available for expanding storage on laptops and gaming systems.
In both formats, smaller 8-16GB cards are fading away as higher capacities become more affordable. And new 2TB cards are on the horizon for power users.
SD vs. Micro SD: Which Should You Get?
So which format is right for you, SD or micro SD? It mainly comes down to compatibility with your particular devices:
- Get SD cards for: DSLR cameras, digital camcorders, laptops, Nintendo Switch, GPS devices, dash cams, drones.
- Get micro SD for: Smartphones, GoPro/action cams, tablets, Chromebooks, handheld gaming, drones, dash cams.
Choose the appropriate card size to match your device’s SD or micro SD slot. Devices like laptops and high-end cameras typically use SD, while phones and tablets need micro SD. Some gadgets support both formats.
Beyond that:
- Micro SD is the way to go if you want maximum portability and convenience across devices.
- Go with SD cards for professional media use if you need reliability, durability, and consistently fast write speeds.
- Get higher capacity SD cards (128GB+) for storing more hi-res photos and video footage.
- Micro SD cards offer more affordable options for basic storage expansion.
Shop for a reputable brand – SanDisk, Samsung, Lexar, Sony, Kingston, etc. Look for cards rated Class 10 or faster for good performance. And get the appropriate size to fit the device you’ll be using it in. With both SD and micro SD cards widely available, you can easily get the best type of removable flash memory for your particular needs.
Conclusion
SD cards and micro SD cards serve similar purposes as removable flash-based storage for consumer electronics. But their different size and performance attributes make each one better suited for particular use cases.
The miniaturized micro SD format is designed specifically for compact mobile devices where small size is critical, like smartphones and action cams. Their tiny physical footprint allows micro SD cards to fit into the slimmest gadgets that are pushing the limits of how thin devices can be made.
Meanwhile, the larger SD card is ideal any time both speed and capacity are important considerations on top of size. SD remains the standard for large-capacity storage expansion in laptops, high-end cameras, gaming systems, and more. Their extra surface area allows for greater reliability and heat dissipation during intense read/write activities.
Ultimately it comes down to finding the right card type and capacity for your specific devices’ slots and storage needs. With affordable pricing across the range of offerings, both SD and micro SD continue to be the removable storage formats of choice for consumers who need portable, high-capacity memory to hold their photos, videos, music, apps, and files.