Data Storage Converter
Convert bits, bytes, KB, MB, GB, TB — both SI (1000-based) and IEC binary (1024-based)
Quick answer: 1 GB (SI) = 1,000,000,000 bytes. 1 GiB (binary) = 1,073,741,824 bytes. A "1 TB" hard drive = 931 GiB. This is why your drive shows less space than advertised — the units differ.
SI (decimal, 1000-based)
IEC (binary, 1024-based)
⚠ 1 GB (SI) = 1,000,000,000 bytes. 1 GiB (IEC) = 1,073,741,824 bytes. This is why a "500 GB" drive shows ≈465 GiB in your OS.
SI vs Binary: The Full Comparison
| SI (decimal) | Bytes | IEC (binary) | Bytes |
|---|---|---|---|
| KB (kilobyte) | 1,000 | KiB (kibibyte) | 1,024 |
| MB (megabyte) | 1,000,000 | MiB (mebibyte) | 1,048,576 |
| GB (gigabyte) | 1,000,000,000 | GiB (gibibyte) | 1,073,741,824 |
| TB (terabyte) | 1,000,000,000,000 | TiB (tebibyte) | 1,099,511,627,776 |
| PB (petabyte) | 1,000,000,000,000,000 | PiB (pebibyte) | 1,125,899,906,842,624 |
Frequently Asked Questions
Which operating systems use SI vs binary units?
macOS switched to SI (decimal) units in OS X 10.6 (Snow Leopard, 2009) — so macOS shows a 1TB drive as 1 TB. Windows still uses binary units (GiB) but labels them as GB, causing the apparent discrepancy. Linux distributions vary. Most storage devices, USB drives, and SSDs are marketed in SI units.
How much data is a petabyte?
One petabyte (1 PB) is 1,000 terabytes or 1,000,000 gigabytes. To put it in perspective: 1 PB could store about 13.3 years of HD video, or all the text ever written by humans since the invention of writing. Major cloud providers store exabytes (1,000 PB) of data.
What is the difference between a bit and a byte?
1 byte = 8 bits. Bits are the fundamental unit of digital information (0 or 1). Bytes are used for storage. Network speeds are measured in bits per second (Mbps), while file sizes are in bytes (MB). A 100 Mbps internet connection downloads at 12.5 MB/s (100 / 8 = 12.5).