Digital Storage Converter

The gap between a decimal gigabyte and a binary gigabyte isn't a fixed percentage, and two other unit mismatches in computing trip people up just as often once you look past the basic GB versus GiB confusion.

The decimal gap grows every time you scale up

At the kilobyte level, decimal and binary units differ by about 2.4 percent. At megabyte it's 4.9 percent. At gigabyte it's 7.4 percent. At terabyte it crosses 10 percent. Each prefix multiplies the previous gap by roughly 1.024 again, so the further up the scale you go, the larger the missing chunk looks on a spec sheet. This is why a "lost" amount of storage feels minor on a phone and dramatic on a multi terabyte drive, even though the underlying cause is identical at every scale.

RAM is sold in true binary. Drives are not.

Memory manufacturers report RAM capacity in actual binary gigabytes, because memory is physically addressed in powers of two, a hardware constraint rather than a marketing choice. Storage drive manufacturers, by contrast, market capacity in decimal gigabytes, which produces a larger number on the box for the same physical amount of storage. A computer with "16 GB" of RAM and a "16 GB" flash drive are not using the same definition of gigabyte, even though the labels look identical.

Internet speed and file size don't share a unit family

Internet plans are advertised in megabits per second, while file sizes are measured in megabytes. A byte is 8 bits, so a connection advertised at 100 Mbps tops out around 12.5 megabytes per second of actual download speed, not 100. This single bit versus byte mixup, often shortened to a lowercase versus uppercase "b", is one of the most common sources of "why is my download so much slower than my internet speed" confusion.