Byte / Data Size Converter

How to Use the Byte / Data Size Converter

Enter a numeric value and select your input unit from the dropdown. The converter instantly shows the equivalent data size in all units, split into two columns: binary (1024-based, using KiB/MiB/GiB notation) and decimal (1000-based, using KB/MB/GB notation). Input units use binary (1024) interpretation, matching how most operating systems and software report file sizes.

This tool helps developers, system administrators, and anyone working with data storage or transfer understand the real differences between binary and decimal data size representations. It clarifies why a "1 TB" hard drive shows as only 931 GB in your operating system.

Binary vs. Decimal Data Units

Computer memory is organized in powers of 2 (binary), making 1,024 a natural boundary (2^10). Storage manufacturers and networking use powers of 10 (decimal), where 1 KB = 1,000 bytes. The IEC standardized binary prefixes in 1998: KiB (kibibyte, 1,024 bytes), MiB (mebibyte, 1,048,576 bytes), GiB (gibibyte, 1,073,741,824 bytes), and so on. Despite this standard, many operating systems still display binary values with decimal labels, leading to widespread confusion.

The Storage Discrepancy Explained

A hard drive sold as "1 TB" contains exactly 1,000,000,000,000 bytes (1 trillion bytes, using the decimal definition). When your operating system displays this using binary units, it shows approximately 931 GiB -- but labels it as "931 GB." The difference of about 7% per tier (KB vs KiB, MB vs MiB, etc.) compounds at larger sizes. A "1 PB" system shows as roughly 909 TiB. No storage is lost; it is purely a labeling convention difference.

Which System to Use

Use binary (KiB, MiB, GiB, TiB) when discussing RAM, CPU cache, swap space, and file system allocation -- these are always exact powers of 1024. Use decimal (KB, MB, GB, TB) when discussing hard drive capacity, SSD specifications, network bandwidth, and data transfer speeds -- these industries consistently use powers of 1000. This converter shows both simultaneously so you never have to guess.

Frequently Asked Questions

What is the difference between KB and KiB?

KB (kilobyte) in the decimal system equals 1,000 bytes, while KiB (kibibyte) in the binary system equals 1,024 bytes. The IEC introduced the "bi" prefixes (kibi, mebi, gibi) to eliminate ambiguity. Operating systems like Windows traditionally use binary values but label them with decimal prefixes, which is why a "1 TB" drive shows as about 931 GB.

Why does my hard drive show less space than advertised?

Hard drive manufacturers use decimal (base-1000) units: 1 TB = 1,000,000,000,000 bytes. Operating systems like Windows use binary (base-1024) units: 1 TiB = 1,099,511,627,776 bytes. So a 1 TB drive contains 1,000,000,000,000 bytes, which equals approximately 931 GiB when displayed by the OS. No space is actually missing.

How many MB are in a GB?

In the decimal system, 1 GB = 1,000 MB. In the binary system, 1 GiB = 1,024 MiB. Most people use 1 GB = 1,024 MB in practice because operating systems historically used binary calculations with decimal labels. This converter shows both to avoid confusion.

What comes after petabytes?

After petabytes come exabytes (EB, 10^18 bytes), zettabytes (ZB, 10^21 bytes), and yottabytes (YB, 10^24 bytes). In binary equivalents: exbibytes (EiB), zebibytes (ZiB), and yobibytes (YiB). As of 2024, global data creation is measured in zettabytes per year.

Should I use binary or decimal units for file sizes?

Use binary units (KiB, MiB, GiB) when discussing RAM, cache sizes, and operating system file sizes, as these are always measured in powers of 1024. Use decimal units (KB, MB, GB) for storage capacity, network speeds, and data transfer rates, as these industries use powers of 1000. This converter shows both to help you compare.