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Home / Converters / Bytes Converter (KB, MB, GB, TB)

Bytes Converter (KB, MB, GB, TB)

Convert between bytes, KB/MB/GB/TB and KiB/MiB/GiB/TiB — both decimal (base 10) and binary (base 2).

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Frequently asked questions

Is any data sent to a server when I use this tool?
No. All conversions are calculated locally in your browser using JavaScript. No values are transmitted anywhere. This is safe to use with file sizes from private or confidential systems.
Why is 1 KB sometimes 1,000 bytes and sometimes 1,024 bytes?
The ambiguity exists because of a historical accident. When computer memory sizes were first being described in the 1960s and 1970s, engineers used 'kilo' to mean 1,024 (a convenient power of two close to 1,000) because it simplified binary arithmetic. The SI definition of kilo had always been exactly 1,000. These two conventions coexisted for decades until the IEC introduced the KiB/MiB/GiB prefixes in 1998 to formally separate them, but consumer software and marketing materials continue to use KB/GB ambiguously.
Why does my 1 TB drive only show around 931 GB in Windows?
The drive manufacturer uses decimal terabytes (1 TB = 10^12 bytes = 1,000,000,000,000 bytes). Windows calculates and displays storage capacity in binary gibibytes (1 GiB = 2^30 bytes = 1,073,741,824 bytes) but labels them as GB. Dividing 10^12 by 2^30 gives approximately 931.32, which is what Windows shows. No bytes are missing — it is purely a labeling mismatch between decimal marketing and binary operating system conventions.
What are the IEC binary prefixes and why were they introduced?
The International Electrotechnical Commission introduced the binary prefixes kibibyte (KiB), mebibyte (MiB), gibibyte (GiB), tebibyte (TiB), pebibyte (PiB), and exbibyte (EiB) in IEC 80000-13:1998. The names combine the first two letters of the SI prefix (ki-, me-, gi-) with the syllable 'bi' for binary. They were introduced specifically to eliminate the ambiguity of using SI prefixes for both decimal and binary quantities in computing, enabling precise technical writing and specification of data storage without confusion.
Does the difference between KB and KiB really matter?
At the kilobyte level the difference is only about 2.4%, which is small. But the divergence compounds with each prefix: the difference between 1 MB and 1 MiB is about 4.9%, between GB and GiB about 7.4%, and between TB and TiB about 9.9%. For large storage systems, cloud billing, or file system quotas, this 10% gap on terabyte-scale storage can represent billions of bytes and significant money. In technical specifications, contracts, and legal documents, using the correct prefix matters.
What is the history of the byte as a unit?
The word 'byte' was coined by Werner Buchholz in 1956 during the design of the IBM Stretch computer, deliberately chosen to rhyme with 'bit' while being clearly different. Early computers used varying word sizes — 6-bit characters were common in the 1950s and 1960s. The 8-bit byte became dominant with the IBM System/360 in 1964, which made it the fundamental addressable unit. Today, one byte is universally understood to mean 8 bits, though the word technically means any grouping of bits that a particular system addresses as a unit.
Why are network speeds in bits while file sizes are in bytes?
Network speeds are traditionally measured in bits per second because telecommunications standards (telephone lines, radio, serial interfaces) originally measured signal throughput in individual bit transitions. The bit-per-second unit predates personal computing and comes from the world of telegraphy and telecommunications. File storage, by contrast, was always organized in bytes (8 bits) because that is the unit processors address. The mismatch persists today: a 100 Mbps connection transfers 100,000,000 bits per second, which is approximately 12,500,000 bytes (12.5 MB) per second — always divide advertised megabits by 8 to get megabytes.
How does this tool compare to a search engine byte converter?
Search engines typically only convert between a small set of SI units (KB, MB, GB, TB) and do not show binary IEC units (KiB, MiB, GiB, TiB) or explain the difference. This tool shows both systems simultaneously, making the difference immediately visible, which is particularly useful for understanding why your OS reports a different capacity than your drive's box claims.
Which byte conversion values are worth knowing by heart?
The most useful to remember: 1 KB = 1,000 bytes; 1 KiB = 1,024 bytes; 1 MB = 1,000,000 bytes; 1 MiB = 1,048,576 bytes; 1 GB = 1,000,000,000 bytes; 1 GiB = 1,073,741,824 bytes. Also useful: a standard floppy disk held 1.44 MB (actually 1,474,560 bytes, making it neither 1.44 SI megabytes nor 1.44 binary mebibytes — a quirk of its own).
What is a nibble, and are there units smaller than a byte?
A nibble (sometimes spelled nybble) is 4 bits, or half a byte, which corresponds to a single hexadecimal digit. Below the byte there are no standard named units in common use. Bits are the smallest unit. The nibble is occasionally used in discussions of BCD (binary-coded decimal) encoding and in low-level hardware descriptions, but it appears rarely outside of technical documentation and computer science coursework.

About Bytes Converter (KB, MB, GB, TB)

Data storage and network capacity are measured using two parallel unit systems that share almost identical names, causing persistent confusion for consumers and professionals alike. The decimal system, defined by the International System of Units (SI), uses powers of 1,000: one kilobyte (KB) is exactly 1,000 bytes, one megabyte (MB) is 1,000,000 bytes, and so on. Hard drive and SSD manufacturers, as well as network speed specifications, use these SI units because they make their products appear larger and faster in advertising. The binary system, formally defined by the International Electrotechnical Commission (IEC) in 1998, uses powers of 1,024: one kibibyte (KiB) is exactly 1,024 bytes, one mebibyte (MiB) is 1,048,576 bytes. Operating systems, RAM modules, and file system tools traditionally report sizes in binary units — but many still label them with the ambiguous KB/MB/GB abbreviations, making it appear that your storage hardware is missing space.

The divergence between these two systems creates real-world confusion at every level. A 1 TB hard drive contains exactly 1,000,000,000,000 bytes by its manufacturer's specification. Windows reports available storage in binary gibibytes — 1,000,000,000,000 / 1,073,741,824 (which is 2^30) ≈ 931.32 GiB — but labels it as GB. This is why every consumer who has ever bought a storage device has wondered where the missing space went. Network speeds compound the confusion further: internet service providers advertise speeds in megabits per second (Mbps) using decimal, while file transfer software typically shows speeds in megabytes per second (MB/s), also often decimal, meaning a 100 Mbps connection transfers about 12.5 MB/s, not 100 MB/s.

This tool converts between both decimal SI units (KB, MB, GB, TB, PB) and binary IEC units (KiB, MiB, GiB, TiB, PiB) simultaneously. Enter any value in any field and every other unit updates instantly. Calculations use JavaScript BigInt for byte counts so values of any size remain exact with no floating-point rounding. All processing runs entirely in your browser — no data is uploaded.

A few important things to remember: the gap between SI and binary units grows with each prefix — KB vs KiB differ by about 2.4%, but TB vs TiB differ by about 9.9%, and PB vs PiB differ by about 12.6%. This means the larger the storage, the more misleading marketing figures become. The IEC prefixes (KiB, MiB, GiB) were specifically created in 1998 to end this ambiguity, but adoption has been slow outside technical writing. The Linux kernel, macOS (since macOS 10.6), and most scientific and engineering contexts now use the correct IEC prefixes, while Windows and many consumer applications continue to use SI abbreviations for binary quantities.

The 1024 vs 1000 War: How a Standards Fight Left Consumers Confused for Decades

The ambiguity between 1,000 and 1,024 bytes per kilobyte is one of the longest-running low-grade conflicts in the history of computing standards. It began innocently: in the 1960s, computer memory was sold in powers of two, and 1,024 bytes (2^10) was the smallest convenient power of two above one thousand. Engineers informally called this a 'kilobyte' by analogy with the SI kilo- prefix, even though SI kilo strictly meant 1,000. No standard body objected because the difference was small and computing was a niche field. As memory and storage grew through the 1980s and 1990s, the two definitions drifted further and further apart with each order of magnitude.

Hard drive manufacturers, meanwhile, had good commercial reasons to prefer the SI definition. A drive sold as 100 GB using the SI definition (100 × 10^9 = 100,000,000,000 bytes) would be labeled by an operating system as only about 93.1 GiB — a full 7% smaller. The practice was technically accurate under SI, but felt deceptive to consumers who saw their new drive appear smaller than advertised when they plugged it in. Class-action lawsuits were filed against hard drive manufacturers in the United States in the early 2000s. Western Digital settled a suit in 2006 for $1.4 million, agreeing to include clearer labeling, without admitting wrongdoing. Similar suits followed against Seagate and others.

The IEC's 1998 introduction of kibibyte, mebibyte, and gibibyte was intended to end the confusion definitively by giving the binary quantities their own unambiguous names. Adoption has been mixed. The Linux kernel, the GNU project, the International Bureau of Weights and Measures, and the IEEE all now use the IEC prefixes in formal contexts. macOS switched to SI decimal units in version 10.6 Snow Leopard in 2009, solving the apparent gap by reporting storage in decimal gigabytes to match manufacturer labeling. Windows continues to report in binary but label them as GB. The result is that a modern MacBook and a Windows PC connected to the same file server will report the same file's size with different numbers, despite reading the identical bytes.

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