Fact Checked

What are SDHC Cards?

R. Kayne
R. Kayne

About the size of a US postage stamp, a Secure Digital High-Capacity (SDHC) card is a flash memory device that can hold between 4 and 32 gigabytes (GB) of data. These cards are a form of removable memory that can be used with many different digital devices, including camcorders and computers. While there are several other SD card products available, typically only machines that are labeled as working with SDHC cards can use them.


SDHC memory card.
SDHC memory card.

SDHC cards store and transfer information from one compatible machine to another. Many different types of devices, from digital cameras to music players to photo sharing products, made by most different manufacturers have slots that accept these cards. SDHC cards are perhaps most popular for recording and transferring media — including audio, video, or still pictures — from a camera or recorder to a computer so that they can be stored or manipulated. These storage devices function like many others: users can copy and paste files to the card, save files to it directly, or extract information from it.

Classifications and Storage

The Secure Digital High-Capacity card is a type of memory card that can be used with computers, digital cameras and other devices.
The Secure Digital High-Capacity card is a type of memory card that can be used with computers, digital cameras and other devices.

SDHC cards were designed to be an improvement on the original Secure Digital (SD) memory card developed in 1999. The new card helped satisfy the growing demand for high-capacity storage caused by the increasing use of high-definition video and high-resolution digital photography. SDHC cards also offered a new benefit for consumers: classifications of data transfer speed (DTS). Manufacturers categorize these products according to the minimum sustained DTS, grouping cards into four different classifications:

  • Class 2: minimum sustained DTS of 2MB/sec
  • Class 4: minimum sustained DTS of 4MB/sec
  • Class 6: minimum sustained DTS of 6MB/sec
  • Class 10: minimum sustained DTS of 10MB/sec
SDHC cards can be used to store photos and video taken on digital cameras.
SDHC cards can be used to store photos and video taken on digital cameras.

Cards in higher classes can transfer data more quickly in most cases, although this can depend on the card reader. The classes also are set by the minimum DTS, not the maximum, and a user may get much better performance. It's best for the user to test the writing speed of his device and use the recommended class, however, because this performance can be critical for users.

Choosing a Class and Capacity

Cards in the higher classes are useful for people who want to record high definition (HD) video or save many high resolution photos. Someone trying to record high definition video onto a slower memory card, for example, may find that he does not get the quality he expects, if the video records at all. Most experts recommend Class 6 for HD purposes; its speed is typically fast enough for most recordings and it's less expensive than a Class 10 card. Standard SD or SDHC Class 2 is usually fast enough for standard definition recording.

A 32 GB card can hold 4,161 22-megapixel photos compressed or 416 photos of the same size and quality uncompressed. When it comes to video, this same size card can hold 60 two-hour videos shot at 30 frames per second (fps). Users should make sure that their camera or camcorder can handle this amount of storage, however, because some inexpensive devices cannot be used with high capacity cards.

Compatible Devices

Most devices are designed to read a specific type of memory card or other storage method that is the current industry standard, along with many of its predecessors of the same technology, provided they are still available for sale. The opposite is not true, however; most older products cannot read memory cards made with newer technology. In other words, machines that have SDHC card slots can usually use this standard as well as the earlier SD, but those with SD slots typically cannot read SDHC cards. As a result, some companies have created software patches to allow older devices and the newer cards to work together, or made external readers that could be attached through a USB port.

If a product manual does not specifically list high capacity cards as a type of memory that can be used or says that the device is SD specification 2.00 compatible, it cannot use an SDHC card without an external reader. A newer card technology, called SDXC, is also on the market, and most products that accept SDXC cards will also read SDHC cards. Despite this, SDHC-specific devices may not be able to read an SDXC card or usability may be limited.

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Discussion Comments


Thank you for an answer to SD vs SDHC compatibility with older cell phones. I have talked to wireless carrier that sold me the phone, and I have looked in phone's manual (which is a joke unless you're a Wise Geek - manuals never tell you enough or they talk over your head). Thank you!


So what is the deal with SD cards larger then 32gb?


I have an SDHC. I plugged it into my computer's SD card slot and it read it. After it came up, it showed pictures coming up, but when I click on a video it starts to play as if it was in fast forward mode and it plays no audio. Please help!


My Toyota is fitted with a car multimedia system. It has a slot for SDHC. It does not read a 2gb standard SD card with mp3 files. Should I necessarily buy an HDSC card? Please advise on the capacity and class number.


I have a PNY OPTIMA SD HC 120 HD 8 GB card. It holds a lot of pictures. Well, I had it in my computer to transfer my pictures. Went to use it in my camera and it kept saying it was locked. Got it out and pushed the button down several times and tried it back in my camera. Now, I get it out and do it again and the button falls off! I am very upset! I have an 8GB card here that has pictures on it that I have been using for a while and cannot add anymore. I can still view them, thank God, but can't take any more. What do I do?


i just used my new canon e0s 500D with an SDHC Memory card and i can't download the photos to my laptop. Does any software need to be downloaded or to purchase a separate reader.


I used a sandisk sdhc with a canon 60D. I was able to download the photos the first time. The next day I used it again and was able to see the photos. Then the laptop tells me to reformat. I tried photorec but the sd card does not show up at all. any hope of recovering?


I have a Sanyo 4GB SDHC flash card but every time i plug it into my computer (it's an Everex) nothing pops up and it does nothing. how do i make it let me put my pictures on my computer? Please help!


I used an SDHC card for my vacation pictures last week and while they look great on the camera, I can't get my computer to acknowledge the card. Why?


Concerning post 106. The faster card will not improve your video but if you would up your HD settings say from 1440 X 720 to 1920 X 1080 you may choke the card. The class settings on the cards refers to it's lowest fully stable transfer rate and not so much the fastest. This is really important in video production. Sounds like you are using a camera that also shoots HD.

I shoot with pro video cams so I just have no lower than class 6. On my main HD cam I shoot on Class 10. It's better to be safe than sorry! --Tom in Thailand


my camera is showing a memory error and not showing any of the stored images. i have a sony 5gb, sdhc card. please help.


I have a Panasonic HDC-Sd60 and got a class 2 SanDisk 32 gig SDHC card. I got the card before finding out it is recommended I use a card no lower than class 6. I can film and shoot no problem, but would like to know if there would be an increase in video quality if I was to get a higher class card, say a class 10?


I have a ton of pics/video on my camcorder, but never used a memory card yet, just bought one, but if I put it in will it erase all of my data from the hard drive? if not, how do I put my data on my memory card, as I don't have a usb cable to load pics to computer.


how many pictures can you take using a sdhc 4 gb card?


If you buy a camera and it says holds up to 8 gb memory card why can't you use a 16 gb if you want? what will happen?


If your device uses the faster SDHD card then as in my case you may have to get a newer card reader.

My older reader only reads up to 2GB.


What is the maximum capacity SD card the Canon EOS 500D Rebel T1 can use? I can't find it anywhere online. Thanks! -Bryan


My school just purchased four Canon Digital Camcorders,model fs200a. What is the recommended memory card for optimal performance of these camcorders?


anyone know why my compaq v2000 sd card reader won't read a 4gb SDHC from my samsung digital camera.


Could anyone tell me why it takes forever to download pics from my Transend 8gb class 10 sdhc card to my pc. I only have the resolution on 3mill pixels on my camera so its not a memory problem..I don't have this trouble with normal 2 and 4 gb sd cards or my class 2 sdhc cards. help please. thanks.


I tried to transfer a picture from my laptop to an SDHC card and although the laptop can read the card the camera says there are no pictures. Is it possible to do this? I have no problems using the card in the normal way.


I have a 16GB SDHC that my computer will recognize but neither of my two cameras will. One will not turn on and the other says the card needs to be formatted. When I tell it to it tries but then says it needs formatting. I formatted it in my computer but the cameras still won't work with it. What gives?


I bought a 4GB SDHC card for my camera, and although it works in my camera it isn't recognized when I try and connect it to me computer. How do I solve this?


Same problem- SDHC 4GB card with Acer laptop- downloaded updated Texas Instruments version from cnet, restarted the computer, popped the card in and it worked!


I inserted my SDHC card in our tv's SD slot and unfortunately it's not compatible. Did I erase the memory in my SDHC card since it read "no images" on our tv or are my photos still safe and fine? I really need help.



Q:"My computer won't recognize my 4.0Gb sdhc card"

A:Old card readers are only compatible with -up to, and excluding 4GB capicity SDHC cards. Eventually you could get firmware update for card reader, but if it's no-name brand you're doomed like.


My computer won't recognize my 4.0Gb sdhc card. my computer has a vista can you help me to activate my card please?


can i use a 16gb sdhc card in my camcorder? it says it will only take up to 8gb class 6.


I bought a SDHC 32GB Class 10 (SD Specification v3.00) for my father Canon HF200 new (end of 2009) camcorder but it can only shoot photos on it without recording anything.

I can see there is a 32Gb card inserted but don't see time remaining and class. I thought that maybe it was SD Specification v3.00 compliant because it suggests Class 4 or superior and a Class 10 is superior for sure.

I have not found anything about SD Specification reference in the Canon HF200 specifications.

If I put this Class 10 SDHC Card in my old (first half of 2007) Canon A720 IS camera I can use it without problems, both for photos or movies.

Why do I encounter these problems in new Canon equipment?


#79: There is a tab on the side of the card that allows you to lock (a.k.a. write-protect) the card. Slide the tab down to lock the card or slide the tab up to unlock.

#81: There are free file recovery software. Go to CNET's and do a search for "file recovery".

#82: If you have an SDHC card reader or adapter, the videos may either be stored in the same folder as the pictures or in a separate folder. Depending on the camera, the videos may use one of the following formats: .avi, .mpg, or .mp4 Check your camera's documentation for more info.

#83: Check your camera's video settings. There might be an option to change the video resolution between two settings: 640x480 or 320x240. The higher resolution requires more data to be stored which will shortened the available capacity. Switching to 320x240 should give you the 40 minutes. (Also note that taking photos will take up space on the card, thus shortening the available recording time.)

#84: It's likely the card is not compatible with your camera. Check your camera's documentation for what card you can use. Pay particular attention to Class type and maximum storage capacity since some cameras can only address up to a certain capacity.


#42 Yes, a class 6 SDHC card is a relatively fast card.


i had a 32gb sdhc given to me and i just recently tried to use it and it tells me card error on my camera. how do i remedy this? can someone please help me?


I have new fujifilm JZ500 and purchased an SDHC 4gb card Class 4, camera manual states video capacity of 40 minutes but only showing 26 minutes available. Any ideas?


I have a Panasonic HDC501 camcorder and an Integral SDHC card reader. I can offload the photos from the camcorder but for some reason it will not see the video files. I would be grateful for any help with getting the videos on to my XP computer. Thanks


I have a Power Shot SX20 IS Canon. I was using a SDHC Card 4 GB and suddenly it told me the card can't be read. I tried to open the card on my computer but it didn't read it either. then I connected the cable to the camera to the computer and it told me there are no videos or pics on the card!

there are more than 200 pics I want to recover that are priceless for me. Can someone can suggest me what can I do? please.


@anon13425: Canon A610 does not support a 4 GB card.


if your card gets locked how do you unlock it?


I have a canon vixia hf200 camcorder. It suggests using a class 4 sdhc card. Can i use a class 2 card instead? If so, is the sole drawback to using a class 2 - slower transfer speed? Will it record properly but simply transfer slowly? Any immediate help is appreciated. Thank you.


Thank you all for your info. on SDHC-SD card readers. I can go and buy a digital camera with an

SDHC 8GB card + USB 2.0 single slot SD card reader to use with Win.XP with confidence.


To anyone trying to read SDHC (Secure Digital High Capacity) cards on your PC.

Get the Sandisk Sansa shaker kids mp3 player and put your SDHC card in the SD slot then hook the mp3 player to your PC via the player's USB cable. It should show up as a removable mass storage device. I have an class 6 8GB SDHC card for my digital camera and I use this exact method to get the files off the card and this method reads the card just fine. I'm not sure about the larger class cards like Class 10 16GB/32GB. I hope this is helpful.


I bought a SDHC card today and tried hooking it up to my laptop. It said I needed to format it, but it won't let me. It said it can't read the card. How do I fix this? please help.


Thanks for such a nice and descriptive information. I have used SDHC many times and recovered the lost photos in it theory Stellar Phoenix Photo Recovery Software.


According to SDHC storage charts, a 16GB car can record 480-minutes of standard video or 280-minutes of HD video. But transferring that to the computer makes it a whole lot more than 16GB. What kind of compression is used to maintain such high quality?

I also read somewhere that in theory an SDHC has the maximum capacity of up to 2 TB (2048 GB).


I have just bought a SDHC card and the camera tells me "card error" is it faulty or the camera, settings maybe? popeye


I just purchased a Panasonic Lumix DMC-ZR3K Digital camera and I'd like to add an extra memory card to it. What DTS class for the lumix requirement?


I solved the problem by leaving the card in the camera (Panasonic Lumix DMC-FS15) and connecting the camera to the USB port of the computer. Worked perfectly after that.


Can my 4GB SDHC Lexar be tweaked so that it is High Definition - or was the salesman spinning me a yarn?


Olympus cameras take XD cards. they're rectangular.


I had the same problem. I bought a D-SLR camera with a sdhc card and my hp laptop wouldn't read it. I found an integral sdhc card reader on Amazon, only £1:90 works perfectly and a real bargain. They can also be found a Sainsburys but at £5:99.


My hp computer doesn't read my sdhc card. Please help. thank you!


i have an olympus fe 46 X 42, and a SDHC card which can't seem to fit in the card slot, any idea on what to do?


My camera is a Power Shot SD200 Desital ELPH. Can I use an SDHC memory card instead of an SD memory card? Thanks, Mirza


I have a Canon ZR50 camcorder.I tried to use a 4GB SD HC card and it is not working. Can someone help me?


Do you know of any public kiosk stations or photo printing locations that take the sdhc cards?


my hp computer cannot read the 4gb micro sd hd card. how can i get the computer to fix it? help please.


SDHC cards have a little tab on the side that "locks" the card so it can not be written to, to prevent overwriting valuable info you stored on it.

If you buy a new one and the camera says the card is "locked", remove the card, and move the tab to the "unlocked" position.


When you purchase any SDHC card you should also invest in a SDHC card reader. Then XP will read your pics, movies, etc.


The card itself should have a little slide feature on the edge to protect from accidental deletion. Move the slide feature forward or backward whichever is the case to lock or unlock "write-protect."


my camera is telling me "card locked!" with my sdhc. Help! I just spent a fortune on an 8GB card and they won't let me return it!


I brought a SD card for my digital camera, It says card locked. What does this mean?


I bought a Canon sx1is digital camera (not camcorder) and it takes HD movies. If I buy a HD-HCSD card will I be able to take both the videos and the still shots on that card and then will I be able to read it on my existing 3 year old computer? I understand that if I can read it on the computer it will not be shown in HD format unless I have an HD monitor but will I have difficulty with my computer reading a HDHC SD card at all?


can I use my 32gb sdhc with ipaq hx1200. Do I need to download a driver for the pda


i have an asus nova which has an internal SD reader, but as per above it cannot read SDHC.

Can i download a driver for the internal reader of my asus nova to read the SDHC card or i just to buy a reader that reads SDHC to save all the fuss?


how can i download music on my sdhc card for my nintendo dsi?


Class 6 just means it is 6mb/s or faster, or 40x or faster. So I could buy one card that is actually 150x, or another that is 40x, and they'll both be class 6, but I won't know which one is faster or better. How can I tell what the actual speed of the card is?


If you are having trouble *seeing* your SDHC card *make sure your device can handle* SDHC. Any PDS MFG is going to list what it can take on it's spec page. If it takes SDHC, it will generally accept *most* SDHC unless otherwise noted with a restriction (i.e. up to 8gb only).

Your PC does not need to "have" SDHC compatibility -- the *device reading* the SDHC card needs it.

So *yes* your PC can see it *if* you are using a compatible device. If you have an SDHC card, *always* make sure your device can support SDHC!


I recently purchased a Dane-Elec microSDHC 4GB flash card. It came with a full-size SD adapter and a USB adapter. I cannot get the USB adapter to function with the microSDHC card, but it does work with a microSD card. Is there a driver update I need?


I am thinking of buying a canon ixus 110 with HD movie capture. Do I need to get a 32 sdhc card to store the movies and how much movie footage would I get on say a 4gb card?


Class 6 offers 6MB(Megabyte)/s transfer rate that is 6x8=48Mb(Megabit)/s, right? So it handles HD video well that requires 17Mbs or 24Mbs like Sony CX11 or Canon HF100.

Many times and in many places, they keep messing up with MB/s and Mb/s.


Is a class 6 sdhc the same as high-speed a sdhc card?


Is an sdhc memory card compatible with a sd memory card?


I bought a verbatim SDHC card.. But when I inserted it on my iPAQ hw 6500.. The PDA can't read it.. Is the SD card incompatible with my PDA or what? Pls.. I really need help..


I bought an 8GB Lexar SDHC card but when I formatted it to the SD 2.0 standard it created one primary partition of 4 GB with the rest as unallocated space. So I can use only 4 GB on any of my computers. I am still looking for a fix for this. Does anyone have any ideas?


Umm Hello, My I Ask What Does The HC Part Stands For? Is The Exact Same As Just Normal SD


RE: Posted by: anon2018

Can a SDHC card be utilized in a Sony DSLE Alpha-100, please?

Um... you know that the Alpha 100 uses Compact Flash right? Not SDHC or any other variant. Have you read your manual?

You can buy extremely fast Compact Flash Cards, I use them with my Alpha.


Regarding the 'locked' card from anon13425, I expect his is referring to the 'write-protect' slider on the side of the card, which you can use to suggest to devices that they do not to write to it.


Hello.. Ive got SDHC card in my device (creative zen) and when I connect it with my computer with USB port, the PC doesn't recognize the card, but only the device (zen).. Can you help me with it ?


I ordered a 16GB class 6 SDHC card for my Canon HG20 HD camcorder. I already know it won't work on my SD card reader on my PC. And I know I can get a USB SDHC adapter reader that will work. Is there a firewire SDHC adapter that will work?


You need a freakin compatible sdhc reader for pc!!!!! To use a sdhc card all devices including your pc must be compatible!


I just bought a 4GB Ultra II SDHC card made by SanDisk. The picture on the website showed Class 4. However, when I received it, it is Class 2. Strangely, the product number (SDSDRH-004G-A11) and bar code (19659 02900) are exactly the same as the one that I bought from BestBuy (Class 4). I also checked SanDisk's website and did not see any Class 2 SDHC with 4GB capacity. Is the one I just bought a fake product or a good one, but old version?


I realize that an SDHC card will not read on an older SD reader, but does anyone know if you can upgrade drivers or firmware to make it work?


If you have a SDHC card and you are trying to use it on "legacy" SD card readers or devices, it will NOT work. You need to acquire a new reader or device or, just plain return it. If you have a 4gb+ card, you can bet it won't work on the old hardware.


Hello: I need to know the DTS (data transfer speed) of a Fujifilm S1000 fd digital camera. I have searched for specifications and I can find everything but its DTS. Could you please help me? Thanks in advance.


I just purchased a 16gb SDHC card online, when i try to format it freezes my laptop completely. my laptop reads the card because it shows 15.6gbs of space on it but needs to be formatted but when i try it freezes my laptop anyway to fix or is there away format it with out having my laptop freeze on me trying to format?


I'm thinking about getting a Canon HF100 Camcorder. I think it can record at 17Mbps. I'm guessing that is megabits per second and that is a little over 2MB (Mega Bytes per second - Is that correct?

If so then according to the article the DTS class 2 is a little under and a DTS class 4 would be plenty of speed - am I interpreting this correctly?


Will a SDHC Card hold more data than a SD Card?


I have a microsdhc 8GB card and no adapter. I have an older microsd adapter. Are the microsd adapters good for microsdhc cards? Yes, I know I will need a microsdhc compatible reader to plug the adapter into. Thanks in advance.


"if you have to ask...the answer is 'no'". Absolutely the stupidest computer advice I've ever read. Why do you even bother posting? If the answer to every computer problem was no you wouldn't even have one at your desk to use.

And also, everything in technological advancement has started with a question.


I have a canon powershot A610 digital camera. I bought a SDHC 4GB memory card, but once i put it in the camera, it reads that the card is 'locked'. I have tried everything to 'unlock' it, but nothing. Can you help?


i found that one kodak camera i have will read the hc card and the other camera and the computer with xp will not. the camera that will read the card will also let the computer download the pictures as long as i go through the camera. if i put the card in the computer its no go.


SDHC cards are best for fast and high-quality digital cameras.


jhh4328 - what i've seen is that 2048GB is the theoretical maximum capacity for a SDHC card. but i think the most they've actually produced so far is a card with 32GB. but, technology advances so quickly so i'm sure bigger capacity cards will be coming quickly.


I recently read in a product review for a MicroSDHC memory card that allows for cards all the way up to 2048GB (that's two terabytes!).

Anyone know if the SDHC can be made to hold 2048GB?


You can purchase a SDHC adapter made by SanDisk. You plug the SDHC card into the adapter, then plug the adapter into your USB port. The system recognizes it as a removable hard disk drive. Compatible with up to 8GB cards.


just got a sd-hc for my canon camera, the camera reads it fine but my computer doesn't, but it will if i connect the usb cable. still looking for solutions, thanks


SDHC cards usually won't read in devices that were designed for SD only. Make sure the device or card reader says SDHC on it. My newer Canon camera reads and writes SDHC, but I had to buy a new card reader for my computer because my old one only did SD.


The rule seems to be: if you have to ask, then the answer is no. SD HC is not the only catch in shopping for memory cards; I have a device (digital radio) with a 1 Gbyte limit. SD cards work in SD HC sockets - and mini SD and micro Scards with a suitable adapter - but never the other way around. If your device doesn't have the SD HC mark then that's that - unless you have another interface such as USB to which an SD HC slot can be connected.

I found online an assertion that SD HC cards emulate the FAT32 data format for hard discs, whereas SD is FAT16, so that would stump you as well, if it's true. It's also stated that FAT16 only functions for size up to 2 gigabytes, but I'm even less sure about that.


I have a older hp, it has windows xp with a hundred sixty GB Hard Drive and one GB of ram. I recently purchased a Canon digital camera and a Panasonic four GB SDHC card. After installing the software that came with the package I put my SDHC card in the computer and it will not even recognize that it's in. When I go to my computer the computer freezes up until I remove the card. Can any one help me?


Hi! I purchased a SDHC 4GB purportedly for use in my dvd-camcorder, but to no avail it does not work with it..please help me, is there any driver to be installed so my dvd-camcorder would recognize it? thanks!


Bobbend - As long as the device you are trying to read the SDHC card is SDHC compatible then you should be able to read it without any extra drivers. I purchased a 4GB SDHC card from Costco, and it came with a little black reader device (just a little bit larger than the SDHC card itself). I plugged the card into the reader then plugged the reader into a free USB port and it read the files and photos without any extra drivers. -Kevin


My computer won't recognize my 4.0GB SDHC card. I'm running win XP - SP2. Do I need to install a new driver? Any suggestions?


Yes - an SDHC compatible reader will allow your computer to see the SDHC card.


Will a new card reader make my computer see the SDHC card I just bought?


Is there a software upgrade for products that utilize SD specification 1.0 or 1.1, to 2.0???


My computer won't recognize my 4.0GB SDHC card. I'm running win XP - SP2. Also tried with a USB / SD adapter, still no luck. Any suggestions?


Can a SDHC card be utilized in a Sony DSLE Alpha-100, please?


Is the detailed SDHC specification available somewhere? Specifically, I'm looking for the exact differences between SD and SDHC.

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    • SDHC memory card.
      SDHC memory card.
    • The Secure Digital High-Capacity card is a type of memory card that can be used with computers, digital cameras and other devices.
      By: stocksolutions
      The Secure Digital High-Capacity card is a type of memory card that can be used with computers, digital cameras and other devices.
    • SDHC cards can be used to store photos and video taken on digital cameras.
      By: Kletr
      SDHC cards can be used to store photos and video taken on digital cameras.