Data Storage Converter
Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes and petabytes. Switch between SI (1000-based) and IEC binary (1024-based) standards.
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SI: 1 KB = 1,000 bytes (storage manufacturers, hard drives)
Why 1 GB Is Not Always 1,000,000,000 Bytes
Hard drive manufacturers use the decimal (SI) standard: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes, 1 GB = 1,000,000,000 bytes. Operating systems traditionally used binary: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes, 1 GiB = 1,073,741,824 bytes. This is why a 500 GB hard drive shows as ~465 GB in Windows — the OS is displaying gibibytes.
SI vs IEC — Which to Use
For hard drive and SSD capacity as advertised: use SI (decimal). For RAM and file sizes as shown by your operating system: use IEC (binary). For programming and networking specifications: check the documentation — it varies by context.
Frequently Asked Questions
Drive manufacturers measure 1 TB as 1,000,000,000,000 bytes (SI decimal). Windows shows the capacity in gibibytes (GiB) using powers of 1024. 1,000,000,000,000 / (1024^3) = 931.32 GiB. The data is all there — it is purely a difference in how the two standards define a gigabyte.
A bit is the smallest unit of digital information — a single 0 or 1. A byte is 8 bits. Most file sizes and storage capacities are measured in bytes. Network speeds are often measured in bits per second (Mbps, Gbps), which is why a 100 Mbps internet connection transfers at around 12.5 MB per second.
In SI decimal (used by hard drives): 1 TB = 1,000 GB. In IEC binary (used by operating systems): 1 TiB = 1,024 GiB. The practical result is that a 1 TB hard drive has about 931 GiB of usable space as shown by your OS.
Petabytes (1,000 TB in SI) are used to describe the storage capacity of large data centres and cloud platforms. Companies like Google and Facebook process multiple petabytes of data daily. A petabyte of text would contain roughly 20 times the text of all US academic research libraries combined.
RAM addressing is binary at the hardware level — memory chips are organised in powers of 2 because binary logic maps directly to powers of 2. A memory chip with 32 address lines can address 2^32 = 4,294,967,296 locations. This is why RAM capacities are always exact powers of 2.