Understanding the Difference Between GB and GiB or Why My Memory Card Shows Less Space

Have you ever bought a memory card only to find that your operating system shows less available space than what you expected? If so, you're not alone. This common confusion often arises from the distinction between two units of storage: gigabytes (GB) and gibibytes (GiB).

GB vs. GiB: Decoding the Distinction

GB (Gigabyte): This is the storage capacity unit familiar to most people. It follows the decimal system, where 1 gigabyte equals 1,000 megabytes, 1 megabyte equals 1,000 kilobytes, and so forth. Manufacturers use this standard when labeling storage devices, such as hard drives and memory cards. Hence, when you purchase a 128GB memory card, it's measured in this system.

GiB (Gibibyte): This unit operates on the binary system, where 1 gibibyte equals 1,024 mebibytes, and 1 mebibyte equals 1,024 kibibytes, and so on. Your computer's operating system calculates storage using this system. Thus, when you see 119GiB on your device, it's equivalent to 128GB in the decimal system.

Understanding the Discrepancy

The disparity emerges because manufacturers use the decimal system, which makes the storage capacity seem larger when labeled in GB. However, your computer's operating system reports it in GiB, appearing slightly smaller. For clarity, here's the conversion:

1 GB (decimal) ≈ 0.931 GiB (binary)

For instance, when you buy a 128GB memory card, it remains 128GB in the decimal system but translates to approximately 119.1GiB in the binary system. Hence, you observe less available space in your OS.

Key Considerations for Users

When investing in storage devices like memory cards or hard drives, comprehending the difference between GB and GiB is crucial. The labeled capacity in GB consistently appears larger than the usable space in GiB due to the definitions of these units. This awareness ensures you acquire the needed storage capacity for your data. While it might seem like you're encountering a shortage of space, the advertised capacity remains intact—it's simply represented differently in your operating system.