To make it very clear and easy to grasp, how many photos can a memory card hold is solely dictated by the memory card’s storage capacity and the size of the photos. The increasing trends of image file sizes, however, are on par with the growing trends in memory card capacities.
Previously, the measurements were limited to megabytes (MB), but now they have been widely extended to gigabytes (GB) and even terabytes (TB). But, to keep up with the current phase, you still have to rely on the classic conversions, such as 1Gigabyte (GB) = 1024 Megabytes (MB) and 1 Terabyte (TB) = 1024GB.
In this article, you will discover not only the current image storage capacity of memory cards but also which crucial elements affect it. At the same time, you will know the most suitable type of memory card for each purpose.
How Many Photos Can a Memory Card Hold Per GB
The number of photos you can keep in a GB of storage is an answer that needs to be explored through a series of steps; the first one being megapixels (MP), a unit used to denote the resolution of an image. The higher this number, the bigger the file size of the photograph.
More space being occupied by a photo instantly means that fewer pictures will be on the memory card. The chart below shows this very clearly:
Table: Number of Photos Stored per GB Based on Photo Resolution
| Photo Resolution (MP) | File Size (MB) | Number of Photos Per GB |
| 18 | 5.2 | 192 |
| 16.6 | 5.0 | 200 |
| 12 | 3.6 | 277 |
| 11 | 3.3 | 303 |
| 10 | 3.0 | 333 |
| 8 | 2.4 | 417 |
It should be noted that the file sizes mentioned above are just approximately derived from the average estimation. A photo captured with a 12 megapixel camera would, on average, range from 3.3MB to 5MB in file size. The main point is that the more the resolution of the image, the more space it will occupy.
Photo Storage Capacity on Different Memory Cards
Once you have the file size of the image, you can quickly get an idea of the storage capacity of a particular memory card. Convert the memory card size to a unit of file size. Then apply the following formula:
Theoretical number of images = Memory card size ÷ File size of an image
Yes, theoretical number, you’ve seen it right. The images do not fill every spot on the memory card; some spaces remain empty.
So, the obtained figure will give an idea of close to the exact number of pictures. This will help you understand the maximum number of photos you need to send for storage.
Table: Number of JPG and RAW images in different sizes of memory cards
| Memory Card Size | Total Number of Photos of Different Formats | |
| JPG (7MB) | RAW (35MB) | |
| 32 GB | ~4,671 | ~926 |
| 64 GB | ~9,352 | ~1,862 |
| 128 GB | ~18,714 | ~3,735 |
| 256 GB | ~37,439 | ~7,479 |
| 512 GB | ~74,888 | ~14,969 |
| 1 TB | ~149,786 | ~29,949 |
Factors Affecting the Photo Storage Capacity in Memory Cards
There are some factors that affect the variation of the photo number against a memory card storage capacity. The following aspects crucially contribute to this matter:
The resolution at which the image was captured
You’ve already seen how much impact megapixels have on the file size of the image. On the one hand, where the quality increases, on the other hand, the file size increases.
An eye-catching photo at 12MP creates a file of up to 10MB, while the same picture, more visually stunning at 24MP, takes up around 20MB.
The format in which the image was saved
When taking pictures, many people don’t pay attention to how much storage the image format is taking up. The smallest file is JPEG, where the image is compressed quite a bit.
And the image that has just been captured is RAW until it is edited, which is known as the uncompressed format. They are much larger than JPEG.
There is another format named HEIF, which gives better compression results than JPEG. On the contrary, TIFF files take up more storage space than RAW.
Spaces to Leave from the Size of a Memory Card
Not all of the space on a memory card can be used, and this is where the formula for calculating the number of photos comes into play.
Table: Memory Card Size vs Actual Usable Storage
| Memory Card Size (GB) | Usable Storage (GB) |
| 32 | 28 |
| 64 | 57 |
| 128 | 119 |
| 256 | 238 |
Memory Card Classification
Beyond the number of images they can hold, memory cards vary in terms of data transfer speed. Cards with unique features are as follows:
Compact Flash (CF)
With physically larger dimensions, CF cards offer high capacities and speeds, but are gradually being replaced by newer formats. They are commonly used in professional DSLRs and camcorders.
Secure Digital (SD)
In order to their small size and versatility, SD cards are used most widely and are supported by most laptops, cameras, and smartphones.
MicroSD
Slightly smaller than SD cards, MicroSD cards can be used in SD card slots with an adapter. They are used in devices like smartphones, action cameras, and drones.
CFexpress
As the latest in memory card technology, CFexpress cards provide extremely high speeds and capacities. That’s why they are quite suitable for professional use and high-end cameras.
Table: Comparison of Different Types of Memory Cards
| Card Type | Storage Capacity | Data Transfer Speed (MB/s) | Common Uses |
| Compact Flash | ~ 512GB | ~ 160 | Camcorders, Professional DSLRs |
| Secure Digital | ~ 2TB | ~ 300 | Laptops, Cameras, Smartphones |
| MicroSD | ~ 1TB | ~ 160 | Smartphones, Action Cameras, Drones |
| CFexpress | ~ 2TB | ~ 1,700 | High-End Cameras |
Data Transfer Speed of Memory Cards
SD and microSD cards are further divided into two types, and they are:
- UHS-I (Ultra High Speed-I)
- UHS-II (Ultra High Speed-II)
Here, we break down the core differences between UHS-I and UHS-II SD cards, what you see in the device and what is behind the scenes.
UHS-I vs UHS-II
The UHS-I features a bus interface which allows for transfer speeds up to 104 MB/s, while UHS-II excels with significantly better speeds up to 312 MB/s.
The reason behind it is that UHS-II cards are designed with two rows of pins, rather than one like UHS-I, which allows for two lanes of data transfer.
The higher the transfer speed, the less wait time and the sooner post-production can begin. And that’s why this is perfect for quickly unloading large amounts of data.
Video Speed Class
There is another term called video speed class that indicates the minimum sustained write speed of an SD card. The chart below sheds clear light on the features of the video speed class for various types of memory cards:
Table: Video Speed Class (V10 to V90) at a glance
| Video Speed Class | Data Write Speed (MB/s) | Memory Card Type | Best For |
| V10 | 10 | UHS-I SD | Still photography and full HD 1080p video recording at 30fps (frames per second) |
| V30 | 30 | 4K video recording at 30fps and RAW burst photography | |
| V60 | 60 | UHS-II SD | 6K and 8K video recording at high frame rates and bitrates, multi-file recording at once (RAW + JPEG, still + video + GPS data, time-lapses, multiple video streams created by 360º cameras) |
| V90 | 90 |
How to Choose the Right Memory Card
The factors you should consider when choosing a memory card are data transfer and write speed, capacity and the type of device you’re using it in. Having said that, the selection criteria significantly evolve with your needs and usage.
Smartphones
If you plan to use your phone to shoot 4K videos, choose a microSDXC card with at least 64GB of storage. If not, a 16GB or 32GB microSDHC card is fine for most smartphone users to store photos and videos.
A microSDHC card, which is 32GB, should last for a while before running out of storage space. Many smartphones support microSDXC cards with up to 1TB of storage.
Photography
An advantage of the smaller cards over a big one is that they do not put the risk of losing all photos due to the corruption of the card.
In many mirrorless and DSLR cameras, you can capture many images consecutively by holding down the shutter button. In this case, the data transfer needs to be quick and efficient, especially while shooting in burst mode. That’s why you should get a fast memory card.
Keep in mind that your camera’s specification better be in sync with the speed class.
4K video
V30 or more is best since newer cameras today record 4K resolution at 120fps. A high-rated speed class card supports high bitrates of video and higher quality video recordings.
But your camera needs to have the power to cope with the card’s speed. So, give your camera a proper check for the required speed class.
GoPro
If you are using a GoPro camera to shoot 4K videos, you would have to go for a microSD card with a nice and high-speed class. The 60fps with a write speed of 12MB/s necessitates a microSD card with the minimum V30-rated speed class.
This is a very demanding work that requires high-speed write and good storage at the same time. Even 1080p at 240fps needs a high-speed memory card with good capacity.
But, you should review your GoPro’s specifications to see whether they are well compatible with your microSD card.
Surveillance cameras
When finding a storage card for your surveillance cameras, you will need to take into account what resolution the camera records at. Will the recording only be limited to post-detecting motion, or 24/7? You will never avoid write speed for your purposes here.
Slow write speed distorts your camera footage, as the storage format can not be able to keep up with the recording. Especially when working with exterior security cameras, storage cards should be durable at any cost against the variances in temperature.
FAQ
How much SD card storage should I need for a day out?
It depends on what you’re shooting. If your subjects are cityscapes during the day, that means it would be a few hundred photos a day. Then 64 GB is well enough for raw and JPEG. On the other hand, for visiting a stadium or a zoo, 64 GB is too low, and in this case, you will need at least 128 GB.
What happens if I use a UHS-I card in a UHS-II host?
Your UHS-I SD card will work, but the thing is, the data transfer speed won’t go beyond the maximum speed of the card, which is 104 MB/s. The result is, it won’t be able to use the optimum speed of the host speed.
Can I use a UHS-II card in a UHS-I host?
You’d better not do that. There won’t be an issue in the activation of your UHS-II SD card, but its speed is bound to follow the maximum speeds of the host. So, it can’t work at its fullest potential.
How many photos can a memory card hold when the size is 32 GB?
The answer depends on what resolution the photos were taken. If that is 12MP, the card will store up to 8,889 photos in JPG format. At 16.6MP, the number can be approximately 6,400 and at 24.2MP, the figure is 653.
How many pictures can a 64GB card hold?
If the resolution at which the pictures were taken is 12MP, up to 17,778 pictures can be stored in a 64GB memory card. At 16.6MP, the stored picture number can be 12,800 and at 24.2MP, the figure would be 1,306.
How many pictures can fit per GB in a memory card?
1 GB = 1024 MB, which means that theoretically, the total size of all the photos or one photo storeable in 1 GB will be 1024 MB. But after formatting, the usable space on each card is usually less than its total size.
If the size of a photo is 3.0 MB, then the theoretical number of photos stored per GB is 341, but practically, the number will be a maximum of 333. Similarly, the practical number of photos of 5 MB can be up to 200.
What are the designated Video Speed Classes for UHS-I and UHS-II SDs?
UHS-I cards fall into the V10 or V30 category, but UHS-II cards meet the standardized definition of V60 and V90.
Wrapping Up
You are in the last stage of this discussion, and by this time, you have definitely got the git of the very question: how many photos can a memory card hold? The higher the resolution, the larger the file size, and the fewer pictures can be stored on a card of a specific size.
The choice of CF, SD, MicroSD, or CFexpress is entirely dependent upon your usage needs and device requirements. Just like the size of the memory card, its data transfer and writing speed are not optional.
You have a wide range of options from V10 to V90, but do not forget to recheck the card slot for effective performance, no matter what you select.
Thus, you are well prepared now, and good luck in selecting the most suitable memory card for seamless graphics data management.
