File size, storage capacity, data caps — all of these are measured in bytes, kilobytes, megabytes, gigabytes, and terabytes, and converting between them on paper easily gets confusing because of how many zeros are involved.
What the converter converts
The data size converter converts values between bits, bytes, kilobytes (KB), megabytes (MB), gigabytes (GB), and terabytes (TB). Enter a number into any field, and the other units update instantly.
Why a "terabyte" drive shows less
The converter calculates using the binary scale (×1024), the same one operating systems use to display file sizes: 1 KB = 1024 bytes, 1 MB = 1024 KB, 1 GB = 1024 MB. Drive and SSD manufacturers, on the other hand, more often calculate on a decimal scale (×1000): for them, 1 TB = 1000 GB. Because of that mismatch, a drive advertised by its manufacturer as 1 TB shows up as roughly 931 GB in the operating system — that's not a defect or false advertising, just two different counting systems applied to the same unit.
Bits and bytes aren't the same thing
Internet speed is usually quoted in megabits per second (Mbps), while a downloaded file's size is measured in megabytes (MB). Since 1 byte = 8 bits, a "100 Mbps" connection is about 12.5 MB/s of actual download speed, not 100 MB/s. That mix-up is a common source of confusion over "why doesn't my internet speed match my download speed."
What it's useful for
- Understanding actual file size or storage capacity — converting gigabytes to megabytes or the other way around.
- Estimating an upload limit — comparing a file's size against a cap given in different units.
- Calculating data usage — converting the amount of transferred data between units when reviewing a plan or bill.
Bottom line
The data size converter uses the same binary scale (×1024) as operating systems, so its numbers match what you see in a file explorer or file manager. Understanding the difference between binary and decimal counting explains why a drive's advertised capacity and what your system shows aren't always the same number.