Why are there two answers for the same conversion?
Operating systems traditionally measure storage in binary, where 1 kilobyte = 1024 bytes — that's why a "500 GB" drive shows up as less in Windows or macOS. Storage manufacturers and network speeds, on the other hand, use the decimal definition, where 1 kilobyte = 1000 bytes. Neither is "wrong" — they're just different conventions. Use the toggle above to switch between them.
How to use it
- Choose 1024 or 1000 depending on which convention you need.
- Type the amount and pick your from and to units.
- Hit the round ⇄ button to flip the units, or tap a quick shortcut.
Good to know
Bits and bytes trip people up more often than the 1024-versus-1000 question does. A byte is
eight bits, and the abbreviations differ only by case: Mb is megabits,
MB is megabytes. Internet connections are sold in bits, storage is sold in bytes.
That is why a 100 Mbps connection downloads at roughly 12.5 MB/s rather than 100 — you divide
by eight, not by nothing.
The binary units also have proper names that avoid the ambiguity entirely: kibibyte (KiB), mebibyte (MiB), gibibyte (GiB). They mean 1024-based values unambiguously. Most operating systems still display "GB" while actually reporting GiB, which is the single biggest source of the "my drive is smaller than advertised" confusion.
Worked example
Frequently asked questions
Manufacturers label drives using decimal gigabytes (1 GB = 1,000,000,000 bytes), while Windows and macOS report capacity in binary gibibytes (1 GB = 1,073,741,824 bytes). The drive isn't missing storage — it's the same number of bytes, just measured with a different definition of "GB." Switch this tool's toggle to 1000 to match the number on the box, or 1024 to match what your OS reports.
Both conventions are in real use. Storage manufacturers and network/internet speeds use 1000 (decimal, SI-style), while operating systems and most software traditionally use 1024 (binary). Technically the binary values have their own unit names — kibibyte (KiB), mebibyte (MiB), gibibyte (GiB) — but "KB/MB/GB" is still used colloquially for both, which is exactly why this mismatch causes confusion.
A byte is 8 bits, so converting bits to bytes always divides by 8 regardless of which base (1000 or 1024) you're using for the larger units — the bit-to-byte relationship itself never changes.
A file listed as exactly 1 GB by decimal convention (1,000,000,000 bytes) shows as about 0.93 GB when your computer reports it in binary GB — that 7% gap is the entire source of the classic "where did my storage go" confusion.
Internet and network speeds are almost always quoted in decimal (1000-based) units — for example, a 100 Mbps connection is 100 million bits per second, not 104,857,600. Use the 1000 toggle for anything related to bandwidth or download speed.
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