What’s the difference between SD vs SDHC cards?

We use several types of digital devices, which store data on external memory cards. Unfortunately, just as there is a large variety of digital devices, there is a plethora of memory cards to add to the confusion. People juggle with SDHC, SDXC, SD, MiniSD and MicroSD among the most popular cards. Often it is puzzling to ascertain what type of memory card will suit your camera, phone, MP3 player, tablet or other mobile digital device. Most memory cards are flash type with difference in formats, sizes and speeds.


Apart from Apple products, most digital devices offer means of adding to the internal storage capacity. Typically, this is some variety of the Secure Digital or SD memory card. Although SD has emerged as the most popular flash memory format, there are scores of SD cards of all shapes, sized and speeds to choose from – making it somewhat confusing to pick the right one for your device.

With flash memory cards, the primary aspects that need consideration are their physical format, size and speed. Since each of these variables has its own set of classes, you may find anything from 1GB Class 2 MicroSD card to a 16GB UHS-1 SDXC card.

When buying a memory card, consider where you are likely to use it. Chances are that your camera, smartphone and your camcorder use different sizes of card. Although you can start with the smallest physical format and use adapters to make it fit in different gadgets, it is better to use the card size that is intended for the device.

The largest format is the standard SD card measuring 32x24x2.1mm. Most digital cameras use this format, with high-end cameras shifting to CompactFlash cards, which are smaller. These days, the least frequently used card is the MiniSD card, measuring 21.5x20x1.4mm. Almost all cell phones and smartphones nowadays use the MicroSD card, which has dimensions of 15x11x1mm.

Memory cards come in a huge variety of storage capacities. However, the maximum capacity of a standard SD card is limited to 2GB. The most popular MicroSDHC or Micro Secure Digital High Capacity cards are available with capacities between four and 32GB. The Secure Digital Extended Capacity or SDXC can theoretically range from 64GB to 2TB. However, currently, the largest capacity available is only 128GB.

Larger the memory capacity, so much more you can store. However, if you have an older device, chances are that it can use only the larger SD card. The classification SD/SDHC/SDXC applies to devices as well. Therefore, double-check the type of cards your device can handle. SDHC cards will not work in a device that can handle only an SD card.

Flash cards are available in various speeds as well. The speed class ranges from Class 2 (slowest) to Class 10 (fastest). Class 2 is useful for standard-definition video recording. With Class 4 to Class 6, you can record high-definition video. When you are recording HD video or consecutive recording, Class 10 is more suitable.

If your camera or smartphone can shoot HD video or if you are going to shoot many high-resolution photos in quick succession, you should buy the Class 10 card. For occasional snapshots or casual videos, Class 4 to Class 6 cards will do fine. Prices vary between different types of cards – high-speed high-capacity cards are more expensive.