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What does SDHC mean?

Confused by what SDHC is all about? We have done some research on the topic to help you understand what it all means.


The Basics:

Secure Digital High Capacity (SDHC) is a new design of SD card which was introduced to support higher storage capacities from 4GB to a maximum of 32GB. All SD cards that have capacities of 4GB or more are classed as SDHC and all SD cards that are 2GB or less are standard SD cards. It is important to note that you can only use SDHC memory cards with SDHC compatible devices. In order for you to determine if your device is SDHC compatible look through the user manual for compatible memory cards or alternatively look for the SDHC logo on your device or its packaging. Unfortunately SDHC is not backward compatible with standard SD devices however standard SD memory cards can be used with SDHC devices.

In a little more detail:

The SDHC format is based on the Secure Digital Association (SDA) 2.0 specification which allows SD memory cards to go beyond the previous limitations of 2GB but with a limit of 32GB. The SDA 2.0 specification guarantees a minimum Sustained Data Transfer (SDT) speed rather then a maximum SDT as specified by standard SD (2GB cards and below) memory cards. The SDA introduced three speed class ratings, Class 2, Class 4 and Class 6 of which all SDHC memory cards are classified by.

SDHC has been introduced across the entire range of Secure Digital Cards to offer increased capacities for Micro SDHC, Mini SDHC and of course standard size SDHC cards. Whilst standard SD, mini SD and SD are identical in size and shape with the new SDHC, Micro SDHC, Mini SDHC memory card they are technically different to allow higher capacities. Standard SD cards and devices that comply with SDA version 1.01 and 1.10 are FAT 12 or FAT16 file system compatible. The new SDA 2.0 specification is compatible with the FAT 32 file system for SDHC memory cards and devices.

For further details on SDHC please see If your unsure if your device is SDHC compatible try checking the following Sandisk link

Written by msowa at 14/08/2008 17:59:00

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Comments made about this article

Written By N. Mapara on 15th November 2008 at 20:39
Excellent information. Helps a lot to decide which card to go for.

Keep up the Great Work.

Written By Don on 26th May 2010 at 20:31
What does the Class in an SDHC Card Indicate? I see that there are 3 or r Different Classes.
Is one Class Better than another Class? Is the Higher Class Preferred or the Lower Class?
Written By Chris Monks on 5th November 2011 at 13:13
Thanks very much it helped a lot as I was looking in getting a new memory card and needed the advice,

Chris Monks
Written By Bob on 2nd January 2012 at 12:05
Very helpful thank you
Written By Ed on 25th January 2012 at 20:16
Thankyou for the information. really erased the confusion. 10/10 stars for you guys
Written By Terry on 1st February 2012 at 13:50
Thankyou for the information, I now know what SDHC means.
It is sometimes confusing for us older generation, and it is good to find a site that really helps us.
Keep up the good work.
Written By neil rathbone on 3rd July 2012 at 20:01
Answered my question, thank you
Written By Master on 13th July 2012 at 18:49
Hey Don,
Class indicates the writing speed of that Memory Card.
for Eg. If you buy a class 4 memory card you will get data transfer speed of approximately 4Mb/s.
Written By steven on 22nd August 2012 at 00:22
very helpful, thanks!
Written By edward on 16th September 2012 at 09:34
Smashing artical well written and clearly explained keep the very good work up.
Its great to get the answers to what may seem obviousto other users.
Kind regards Edward
Written By MICK on 19th January 2013 at 20:10
thanks for this imformation , went to ARGOS & STAPLES neither staff knew what SDHC meant. I would of bought the wrong card ! so thanks again .

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