Data Size Converter

Binary (IEC) uses powers of 1024: 1 KiB = 1,024 bytes. Decimal (SI) uses powers of 1000: 1 KB = 1,000 bytes. Operating systems like Windows report file sizes in binary but label them as KB/MB/GB. Mac and Linux use decimal. This causes the apparent discrepancy when a '1 TB' drive shows up as ~931 GB on Windows.

In binary (IEC), 1 GiB = 1,073,741,824 bytes (1024³). In decimal (SI), 1 GB = 1,000,000,000 bytes (1000³). Hard drive manufacturers use decimal, which is why a '1 TB' drive actually stores 1,000,000,000,000 bytes — about 931 binary GiB.

Binary: 1 KB = 1,024 B, 1 MB = 1,048,576 B, 1 GB = 1,073,741,824 B, 1 TB = 1,099,511,627,776 B. Decimal: 1 KB = 1,000 B, 1 MB = 1,000,000 B, 1 GB = 1,000,000,000 B, 1 TB = 1,000,000,000,000 B.

Filesystems allocate space in blocks (typically 4 KB). Even a 1-byte file occupies one full 4 KB block on disk. This is why 'size on disk' is always a multiple of the block size and often larger than the actual file size.

Divide MB by 1,024 (binary) or 1,000 (decimal) to get GB. For example, 2,048 MB ÷ 1,024 = 2 GiB. Use this tool to convert any data size instantly by entering a value and selecting the source unit.