Data Storage Converter

Written byOleh Soloninupdated 5 October 2026

Value

A 1024 multiplier: KB, MB, GB and TB here are binary, that is KiB, MiB, GiB and TiB — the way Windows counts. Drive makers count in 1000s.

From

Result

Result1,024

Binary multiples, the way your file manager counts

Convert megabytes to gigabytes and back using the 1024 multiplier your operating system uses. Explains why a 1 TB drive shows up as 931 GB.

There are two competing definitions of a gigabyte and that single fact explains most storage confusion. Drive manufacturers count in powers of ten; operating systems count in powers of two.

This converter uses 1024, the way Windows counts. That is why a drive sold as 1 TB shows up there as roughly 931 GB — nothing is missing, the two sides are just counting differently. Current macOS shows decimal units, as on the box.

How to use

Enter an amount of data.
Choose the unit you are converting from: bits, bytes, KB, MB, GB or TB.
Choose the unit you are converting to. The calculator uses binary steps of 1,024, the way operating systems do.

What your computer will show

Drive makers count decimal gigabytes of a billion bytes each, while Windows divides by 1,024 three times. That is why Windows shows a 1 TB drive as 931 GB and a 256 GB card as 238 GB — nothing is missing. Current macOS counts the way the maker does and shows 1 TB; on Linux it depends on the program.

Every row comes from the calculator on this page.
On the box	Bytes	Shown by the system
256 GB	256,000,000,000	238.42 GB
500 GB	500,000,000,000	465.66 GB
1 TB	1,000,000,000,000	931.32 GB
2 TB	2,000,000,000,000	1.82 TB

Binary units

A byte is eight bits, and every step after that is 1,024 times the one before. Strictly these are KiB, MiB and GiB, but systems and apps write them as KB, MB and GB.

Every row comes from the calculator on this page.
Unit	Equals
1 byte	8 bits
1 KB	1,024 bytes
1 MB	1,024 KB
1 GB	1,024 MB
1 TB	1,024 GB
4.7 GB	4,812.8 MB

What this calculator shows

The converted size across bits, bytes, KB, MB, GB and TB
Binary multiples (1024) matching operating system reporting
Bit-level conversion, useful when a connection is billed in megabits

What to keep in mind

Uses 1 KB = 1024 bytes. Storage vendors use 1000, which is where the apparent shortfall comes from.
Eight bits make a byte, so a 100 Mbps line moves at most 12.5 million bytes a second — about 11.9 MB/s in this converter's binary units.

FAQs

How many megabytes are in a gigabyte?

1,024 in binary counting, which is what your computer shows. Drive makers count 1,000.

Why does my 1 TB drive show 931 GB?

The box counts a trillion bytes, and the system divides that by 1,024 three times: 931.32 GB. Same capacity, different way of counting.

Why is my download slower than my broadband speed?

Broadband is sold in megabits per second and downloads are shown in megabytes, and a byte is eight bits. Divide the megabits by eight for a rough megabyte figure.

What are GiB and MiB?

Unambiguous names for the binary units: one GiB is exactly 1,024 MiB. They exist to tell binary units from decimal ones, though everyday software still writes GB and MB.

How many bits are in a byte?

Eight. 100 MB in binary units is 838,860,800 bits.

Is a kilobyte 1,000 or 1,024 bytes?

It depends who is counting. This calculator and operating systems use 1,024; the SI standard and drive makers use 1,000 — which is why the box always looks bigger.

Worked example

Why a 1 TB drive looks smaller

Input: 1 TB as the manufacturer counts it (1,000,000,000,000 bytes)

Output: 931.32 GB in binary units

Note: The drive holds exactly what it says. Your operating system is dividing by 1024 three times while the box divided by 1000.

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Result

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