What is the capacity of a 32GB SD card?

SD cards, or Secure Digital cards, are removable flash memory cards used for storing digital information. They are commonly used in digital cameras, camcorders, smartphones, tablets, and other portable devices to expand storage capacity. The main uses of SD cards are to store photos, videos, music, documents, apps, and other files.

SD cards come in a range of storage capacities, from a few gigabytes to over 1 terabyte. The capacity determines how much data you can save on the card. Choosing the right capacity SD card is important to ensure you have enough storage space for your needs.

This article will focus specifically on explaining the storage capacity of a 32GB SD card. We will look at how much data can be stored on a 32GB card and how to make the most efficient use of the available space.

SD Card Basics

SD cards were first introduced in 1999 through a joint effort between SanDisk, Panasonic, and Toshiba as an advancement over MultiMediaCards (MMC) [1]. The SD format was based on SanDisk’s smaller TransFlash memory cards and aimed to offer greater capacities and speeds compared to MMC cards. The first SD cards had capacities up to 128 MB [2].

Physically, SD cards are 24 mm x 32 mm x 2.1 mm in size, which is midway between the size of an MMC card and a CompactFlash card [3]. They come in three form factors – standard size, mini size, and micro size. SD cards are commonly used in digital cameras, camcorders, media players, gaming devices, GPS units, audio recorders, and more. Their ubiquity and versatility have made them one of the most widely adopted memory card formats.

Measuring Digital Storage

Digital storage capacity is measured in units like bytes, kilobytes, megabytes, gigabytes, etc. A byte is the basic unit of measurement and is equal to 8 bits. A kilobyte contains 1,024 bytes, a megabyte contains 1,024 kilobytes, and a gigabyte contains 1,024 megabytes [1]. To convert between the different units, you multiply or divide by 1,024.

For example, 1 megabyte is equal to 1,024 kilobytes. To convert 5 gigabytes to megabytes, you would multiply 5 x 1,024 = 5,120 megabytes. Similarly, to convert 300 megabytes to kilobytes, you would calculate 300 x 1,024 = 307,200 kilobytes [2].

Understanding the relationships between bytes, kilobytes, megabytes, and gigabytes is essential when working with digital storage and determining the capacity of storage devices.

SD Card Capacities

SD cards come in a range of storage capacities to suit different needs. The most common capacities available are:

  • 2GB
  • 4GB
  • 8GB
  • 16GB
  • 32GB
  • 64GB
  • 128GB
  • 256GB
  • 512GB
  • 1TB

Higher capacity cards allow you to store more photos, videos, music, and other files. However, the actual usable storage capacity is always slightly less than the advertised capacity. This is due to a couple factors:

Some space is used up by the file system and formatting of the card. Also, storage capacities are calculated using decimal math (base 10) while computer storage uses binary math (base 2). So 32GB of advertised capacity equates to approximately 29.8GB of usable storage.

Citing: https://www.kingston.com/en/blog/personal-storage/microsd-sd-memory-card-guide

32GB SD Card Details

A 32GB SD card has a total storage capacity of 32 gigabytes or 32 billion bytes. This provides enough room to store a substantial amount of data.

For photos, a 32GB SD card can hold approximately 2,500-5,000 images depending on the camera resolution and JPEG compression used. Shooting RAW files which are larger can store around 500-1,000 photos. At an average of 4GB per hour, a 32GB SD card can store around 8 hours of 1080p HD video.

For audio, a 32GB SD card can hold around 8,000 MP3 songs. When formatted to FAT32, the 32GB SD card has a maximum individual file size of 4GB, allowing it to store movies and other large files.

The actual storage capacity will vary slightly by manufacturer and camera model. But in general, a 32GB SD card provides ample space for most casual photographers and videographers.

Maximizing 32GB SD Card Storage

While 32GB may seem like a large capacity, it can quickly fill up with high-resolution photos, 4K videos, and other large files. Here are some tips to optimize storage and manage files efficiently on a 32GB SD card:

Regularly transfer files from the SD card to your computer or external hard drive. Don’t use the SD card as your only storage location. Offloading files frees up space to continue shooting.

Organize files in folders rather than keeping everything on the root directory. This makes it easier to find files later.

Delete low quality images and duplicate files on the card. Only keep your best shots.

Format the SD card periodically to clear out any orphan files. But make sure to backup important files first!

Use the camera’s burst mode wisely, as it can quickly eat up storage space. Burst shots generate many near-duplicate images.

Switch to lower resolution settings if 32GB is consistently filling up too quickly. 1080p video takes up less space than 4K, for example.

Consider using image optimization software to compress images without sacrificing too much quality. This frees up space while maintaining high resolution.

Stick to reputable brands like SanDisk when buying SD cards. Avoid counterfeits which may have less than the stated capacity.

Defragmenting or optimizing through your computer OS can improve the read/write speed and efficiency of an SD card.

Speed Class Rating

SD cards are given speed class ratings that indicate their minimum guaranteed transfer speeds. These speed classes help consumers choose cards that will meet the performance requirements of their devices.

The SD Association has defined several speed classes including Class 2, Class 4, Class 6, Class 10, U1, U3, V6, V10, V30, V60, and V90. The class number represents the minimum write speed in MB/s. For example, a Class 10 card guarantees a minimum write speed of 10 MB/s. Higher speed classes indicate faster performance.

Choosing an SD card with a speed class rating that matches or exceeds your device’s requirements is important for optimal functionality. A lower speed class card may result in poor performance, lag, delays, and other issues. Using a higher speed class card than your device needs won’t improve performance but ensures maximum speeds.

Newer SD standards like UHS-I and UHS-II allow for ultra high speeds exceeding 100MB/s. The U, V, and number designations associated with these standards indicate minimum performance capabilities. Therefore, a V30 card will provide at least 30 MB/s write speed.

While speed classes denote minimums, actual read/write speeds vary between cards based on factors like memory technology. Speed class alone doesn’t determine real-world performance. Comparing detailed specifications for sequential and random speeds provides a better gauge of expected speeds.

Choosing the Right Capacity

When selecting an SD card, one of the key factors to consider is the capacity. The capacity refers to how much data the card can hold, typically measured in gigabytes (GB) or terabytes (TB). Choosing the right capacity depends on your intended use and storage needs.

Higher capacity cards are better suited for storing lots of high resolution photos, lengthy 4K or 8K video recordings, large games and apps, and other memory-intensive media. For example, a 128GB or 256GB SD card would be a good choice for a DSLR camera user who regularly shoots RAW photos and HD video (Source).

Lower capacity cards in the 16GB to 64GB range may be sufficient for basic point-and-shoot cameras, budget smartphones, and other devices with limited storage needs. A 32GB SD card can hold thousands of photos and songs, for instance, making it a versatile option.

Ultimately, the ideal SD card capacity depends on your particular use case. Consider how much media you need to store and choose accordingly. Higher capacities provide more room to grow, while lower capacities offer affordability and portability.

Other Card Capacities

SD cards are available in a wide range of storage capacities besides 32GB. Smaller capacities like 4GB or 8GB are well suited for basic tasks like storing documents or photos from an older camera. According to the B&H Explora guide, capacities up to 32GB are in the SDHC standard, while larger capacities from 64GB to 2TB fall under the SDXC standard (Everything You Need to Know about SD Cards).

Larger SD cards with 64GB, 128GB or 256GB capacities are ideal for demanding uses like 4K video recording and high-resolution photography. The extra space allows you to store more and larger files before needing to offload content to a computer. Top-end SDXC cards up to 512GB or 1TB give advanced users essentially unlimited storage for a mobile device. However, these massive cards are overkill for casual use.

When choosing an SD card, it’s best to consider your storage needs and device compatibility. A massive 2TB card won’t function in an older device limited to 32GB SDHC. Similarly, a basic 4GB card will quickly fill up if used in a DSLR camera. Selecting the right capacity can optimize performance and avoid needlessly high costs.


In summary, a 32GB SD card has a total raw storage capacity of 32 billion bytes or 32 gigabytes. However, the usable capacity is slightly less due to formatting overhead and logical addressing, typically coming to around 29-30GB of usable space. This capacity allows you to store thousands of high resolution photos, hours of HD video, or a combination of media files on a tiny device smaller than your fingertip.

Key points covered in this article include:

  • SD cards use flash memory and controller chips to store data digitally.
  • Storage capacity is measured in bytes, kilobytes, megabytes, gigabytes etc.
  • Higher capacity cards can store more data but may have slower write speeds.
  • 32GB allows you to store up to 10,000 photos or 8 hours of HD video.
  • Usable capacity is lower than raw capacity due to formatting and addressing.
  • Higher speed rating indicates faster read/write speeds.
  • Choose the right SD card capacity based on your storage needs.

With capacities continuing to expand, SD cards offer a versatile portable storage solution for media and other files.