About

Misidentifying a kilobyte as 1000 bytes versus 1024 bytes produces a compounding error that reaches 7.4% at the tebibyte scale. Operating systems report capacity in binary (IEC) units while storage manufacturers label drives in decimal (SI) units. This discrepancy causes users to perceive missing storage. The converter handles both standards simultaneously: SI prefixes (KB, MB, GB) based on powers of 10, and IEC prefixes (KiB, MiB, GiB) based on powers of 2, as defined by IEC 80000-13 and the SI system.

The tool computes all 18 target values from a single input. Precision is maintained to 15 significant digits, the limit of IEEE 754 double-precision floating-point. Values below 0.001 automatically switch to scientific notation. Note: this converter assumes 1 byte = 8 bits. Nibble representation (4 bits) is excluded as it has no standard storage use.

Formulas

All conversions are computed through a common base unit (bytes). The input value is first converted to bytes, then from bytes to every target unit.

V_target = V_input × F_sourceF_target

Where V_input is the numeric value entered, F_source is the number of bytes in one source unit, and F_target is the number of bytes in one target unit.

SI (decimal) prefixes follow powers of 1000:

1 KB = 10³ B, 1 MB = 10⁶ B, 1 GB = 10⁹ B

IEC (binary) prefixes follow powers of 1024:

1 KiB = 2¹⁰ B, 1 MiB = 2²⁰ B, 1 GiB = 2³⁰ B

The percentage deviation between SI and IEC at scale n:

δ = 1000ⁿ − 1024ⁿ1024ⁿ × 100%

Reference Data

Unit	Symbol	Standard	Bytes Equivalent	Base
Bit	b	SI	0.125	2⁻³
Byte	B	SI	1	2⁰
Kilobyte	KB	SI	1,000	10³
Kibibyte	KiB	IEC	1,024	2¹⁰
Megabyte	MB	SI	1,000,000	10⁶
Mebibyte	MiB	IEC	1,048,576	2²⁰
Gigabyte	GB	SI	1,000,000,000	10⁹
Gibibyte	GiB	IEC	1,073,741,824	2³⁰
Terabyte	TB	SI	1,000,000,000,000	10¹²
Tebibyte	TiB	IEC	1,099,511,627,776	2⁴⁰
Petabyte	PB	SI	1,000,000,000,000,000	10¹⁵
Pebibyte	PiB	IEC	1,125,899,906,842,624	2⁵⁰
Exabyte	EB	SI	1,000,000,000,000,000,000	10¹⁸
Exbibyte	EiB	IEC	1,152,921,504,606,846,976	2⁶⁰
Zettabyte	ZB	SI	10²¹	10²¹
Zebibyte	ZiB	IEC	2⁷⁰	2⁷⁰
Yottabyte	YB	SI	10²⁴	10²⁴
Yobibyte	YiB	IEC	2⁸⁰	2⁸⁰

Frequently Asked Questions

Drive manufacturers use SI units: 1 TB = 1,000,000,000,000 bytes. Operating systems (Windows, older macOS) report in binary units: 1,000,000,000,000 ÷ 1,073,741,824 ≈ 931.32 GiB. No storage is missing. The discrepancy is purely a labeling inconsistency between SI and IEC standards.

Use IEC binary units (KiB, MiB, GiB) when discussing RAM, cache sizes, page sizes, or any context where hardware addresses memory in powers of 2. Use SI decimal units (KB, MB, GB) for network bandwidth, data transfer rates, and storage marketing labels. Mixing the two introduces a compounding error of roughly 2.4% per prefix tier.

The converter supports units up to Yottabyte (10²⁴ bytes) and Yobibyte (2⁸⁰ bytes). These are the largest standardized prefixes defined by SI and IEC 80000-13. Beyond this, JavaScript's IEEE 754 double-precision loses integer accuracy past 2⁵³, so extremely large exact-integer results should be verified with arbitrary-precision tools.

One byte equals 8 bits. The converter treats 1 bit = 0.125 bytes. This is the universal standard (ISO/IEC 80000-13). Fractional byte results are valid and displayed with full precision. This is useful for calculating bandwidth where rates are given in Mbps (megabits per second) and you need MB/s (megabytes per second).

JavaScript uses IEEE 754 double-precision floating-point numbers, which guarantee 15 - 17 significant decimal digits. Any conversion result requiring more precision than this is subject to floating-point rounding. For most practical data storage calculations, 15 digits provides ample accuracy. The converter automatically switches to scientific notation for very small or very large values to preserve readability.