Data storage converter

Hard drive and SSD manufacturers use decimal prefixes (1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, and so on), which produce larger-looking numbers on the box. Operating systems report storage in binary prefixes (1 KiB = 1,024 bytes), which is why a "500 GB" drive appears as roughly 465 GiB in Windows or macOS. Both are "correct" — they're just counting in base 10 versus base 2.

Before 1998, "kilobyte" was used ambiguously for both 1,000 and 1,024 bytes, and the ambiguity got worse at larger scales — the gap between a decimal and binary gigabyte is about 7%. The International Electrotechnical Commission (IEC) introduced kibibyte, mebibyte, gibibyte and so on specifically to mean the binary values unambiguously, leaving kilobyte, megabyte and gigabyte to mean the decimal values. The old names are still widely used both ways in practice, which is exactly why this calculator shows both side by side.

A byte is 8 bits. Network and internet connection speeds are conventionally quoted in bits per second (e.g. a "100 Mbps" connection), while file sizes are conventionally quoted in bytes — which is why a 100 Mbps connection downloads at roughly 12.5 megabytes per second, not 100. Use the "Show bits" section below the main fields to convert between the two.