Data Size Converter
Turn any amount of digital storage into a different unit — decimal or binary — using exact byte definitions.
Exact definitions
Decimal units are exact powers of 1000 and binary units exact powers of 1024, so every conversion uses the official byte value — never a rounded approximation.
Decimal vs binary
KB and KiB are not the same: 1 KB is 1000 bytes, 1 KiB is 1024 bytes. Pick the right family for your context.
What is a data size converter?
One value, any unit
A data size converter changes a digital storage amount from one unit into another — gigabytes to megabytes, megabytes to kilobytes, terabytes to gigabytes, and back. It works by translating every unit through a single shared base, the byte, so any pair of units can be converted with one consistent rule. This tool covers ten common units across both the decimal (SI) and binary (IEC) families, making it useful for sizing files, planning storage, reading download speeds, and anywhere data measured in different conventions needs to meet.
Each unit has an exact size in bytes. To convert, the value is first turned into bytes, then into the target unit.
Result = value × (bytes per from-unit) ÷ (bytes per to-unit)Because the unit sizes are exact definitions — 1 KB = 1000 B, 1 MB = 1,000,000 B, 1 GB = 1,000,000,000 B in the decimal family, and 1 KiB = 1024 B, 1 MiB = 1,048,576 B, 1 GiB = 1,073,741,824 B in the binary family — the result is mathematically exact, limited only by how many decimal places are displayed. The same single rule handles every direction, so converting megabytes back to gigabytes just swaps which factor divides.
Suppose you want to convert 1 gigabyte into megabytes.
Find the base size
One gigabyte is, by definition, 1,000,000,000 bytes.Divide by the target factor
A megabyte is 1,000,000 bytes, so 1,000,000,000 ÷ 1,000,000 = 1000.Read the result
1 gigabyte converts to exactly 1000 megabytes.
The key thing to understand is which family you are in. Decimal units — KB, MB, GB, TB — are powers of 1000 and are what storage manufacturers and the SI standard use, so a drive sold as "1 TB" holds 1,000,000,000,000 bytes. Binary units — KiB, MiB, GiB, TiB — are powers of 1024 and are what most operating systems use internally to report sizes. The two diverge as the numbers grow: that same 1 TB drive shows up as roughly 931 GiB in a file manager, because 1 TB ÷ 1024³ ≈ 931.32 GiB. The drive did not shrink — the operating system is simply counting in 1024s while the box counted in 1000s. When you compare two sizes, make sure both use the same family.
The arithmetic is exact; the only limit is display precision and naming ambiguity.
Bits, bytes, and the 'KB' ambiguity
There are 8 bits in 1 byte, so a connection rated at 100 Mbit/s transfers about 12.5 MB per second — bits and bytes are easy to mix up. In everyday speech "KB", "MB", and "GB" are often used loosely to mean the binary 1024-based amounts, even though strictly they are decimal 1000-based units; this tool keeps the two families separate and exact, so always pick KiB/MiB/GiB when you mean the 1024-based value. Results are rounded to six decimal places, so converting between units that differ enormously in size can lose the last digits.