MB and GB: binary (1024) or decimal (1000)?
Understand why Windows and macOS show different sizes and how to convert correctly.
When you buy a 1 TB SSD, the manufacturer uses the decimal system: 1 TB = 1,000 GB = 1,000,000 MB. Windows and other systems may display space in gibibytes (GiB), base 1024, which is why the "free" number looks smaller.
Decimal (SI) — 1000
Used in disk marketing, USB drives, mobile data plans, and many cloud services when advertising capacity. 1 KB = 1,000 bytes.
Binary (IEC) — 1024
Common in RAM, partitions, and system tools. 1 KiB = 1,024 bytes. Confusing MB with MiB causes capacity calculation errors.
How to convert
Use our byte converter to translate values between units and compare decimal vs binary on the same screen.
Try the tool: Byte Converter