As phone mega pixels increase and everyone slowly starts to get action cams there is an ongoing need for more mobile storage, if you are contemplating upgrading your memory and unsure of the exact things to look for here are our top factors.

Check you device first.

Take the battery out, look at the card slot, hit up Google or the manual, get the basic size and type of card, it might be referred to as flash, SD or even just memory card. Once you know this info you have the basic compatibility rules.

SD cards properties

Once you know your limits check these 4 things and then you are all clued up on what to buy.

  • The Physical Size – get the SDMicro, you can always adapter up to a larger size.
  • The Data Protocol – Get SDHC if you are not sure or cant find the devices card specs.
  • The Capacity – Whatever your budget and protocol dictates, 32gb is heaps for most things.
  • The Card Speed – Class C10 or U1 will ensure  the card is fast enough for your future devices too.

If you are a newbie and after more information, a more detailed overview of each of these are below.

SD cards Physical size

There currently exists 3 SD cards sizes, from the original cards measuring 32 x 24 mm; they are still common and widely used in digital cameras. The emergence of smartphones and more recently action cameras led to manufacturing of more compact SD cards, the MiniSD card measured 21.5 x 20mm which was short lived and followed by the now popular MicroSD sized SD cards which measures 11 x 15 mm.

sd cards
The official SD card sizes, the mini SD card in the middle is rare and hardly used in anything and the micro on the right is used in almost all mobile phones and action cameras.

Smaller Memory cards are the most versatile

The full sized cards used to be faster than the mini and micro cards, nowadays tho they are similar, if your device uses a larger SD card id still recommend getting a smaller card not only can you just use an adapter to upsize it to fit you also have the advantage of using it in other devices. Having an  android and video camera is the best example of this in play, I can take photos/videos with my camera then edit them on my phone using the same memory card.

The only down side is they are a lot harder to look after, they’re small easily dropped without noticing and can easily be lost.

SD card Data Protocol.

Sd speed cards

SD cards have 3 different types, SD, high capacity SDHC, and the eXtended capacity SDXC cards, the main difference is the maximum size the protocol will support. Most current devices take SD and SDHC so if you are eyeing up something over 32GB double check you can support SDXC.

A quick SD History Lesson

  • SD Launched in 1999. The initial SD card protocol could only hold data in either FAT-16 format or Microsoft FAT-12 format for up to 2 gigabytes of data, there were lower denominations of storage capacity available even 16mb memory cards were common, remember that is a time before 1mp cameras when 1MB was a lot of space. They are almost phased out as its 2GB limit is not enough for anyone.
  • SDHC launched in 2006. Manufacturers wanted larger memory for their devices and introduced SDHC high capacity cards, which scaled storage to 32 GB data storage,  using the FAT-32 format.
  • SDXC launched in 2013. This uses an Extended File Allocation Table (exFAT) which similar to a computer harddrive can store data of up to 2 terabytes.


SD card Capacity

16 GB has become the stander now, i wouldn’t go lower than that, I use 32 GB in my phone and camera. Each device has the highest SD cards storage capacity it can support, for example, most smartphones can support up to 32 GB cards. Before purchasing make sure your device can support the card.

SD card speeds

Speed indicates how fast to write data in the SD cards. The speed rating is not the actual but speed on the lowest limit. You may find a class 6 SD card working faster than class 10 SD card as performance is not only based on the card but also your device.

The speed ratings

This is the most confusing element in SD cards, there are two speed standards the C and U. The actual speed experience will depend on the device sending data and the receiving device.


The C card rating

There are in different classes and each has a designated logo, with the class number inscribed in the big C. SD class 2 have 2 Mbps speed, class 6 has 6 MBps while class 10 has 10 Mbps or faster. This is an easy way to describe the speeds, for whatever reason tho, they decided not to go past speed 10 and instead made a new standard.

standard speeds
Each number represents the cards Mbps speed.

The U card rating

The U card rating goes beyond the C class and seems to be released in 1,3,5,7,9 and similar to the C rating describes the speed except with a U rating the number is multiplied by 10. The U series is really fast and unless you are recording some 2K or 4K video you really wont notice any difference beyond class 10 (most phones even the difference between class 6  and 10 you wouldn’t notice).

ultra speeds
U1 is equal to C10 and offers speeds above 10Mbps. U3 is above 30Mbps.


I hope this guide has been useful and of some educational value, if you are looking for a new card and don’t need one immediately, we have a great range of memory cards direct form China.

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An informative article with some really useful information. Here is a quick add-on to the paragraph on “SD Card Capacity”: The specifications for many Android devices state that they can support SD Cards up to 32 GB. However, that does not necessarily mean that they won’t work with SD Cards of higher capacity – they may just not be able to support the exFAT format of bigger SD Cards. So, if you want to use say a 64 GB SD Card on an Android device, just reformat the SD Card from exFAT format to FAT32 format, and it will usually… Read more »