Data Storage Converter

Convert bytes, KB, MB, GB and TB to KiB, MiB, GiB and TiB, and see why a 1 TB drive shows 931 GB.

Value

From

1 kB =

0.000001 GB

Formula: GB = kB × 0.000001

KB is read as 1000 bytes; choose KiB for 1024.

In every unit of data storage

Precision

Decimal places

Group digits

Unit	Value	Copy
Bits
Bit	8,000 bit
Kilobit	8 kbit
Megabit	0.008 Mbit
Gigabit	0.000008 Gbit
Bytes, decimal (1000)
Byte	1,000 B
Kilobyte	1 kB
Megabyte	0.001 MB
Gigabyte	0.000001 GB
Terabyte	1 × 10⁻⁹ TB
Petabyte	1 × 10⁻¹² PB
Bytes, binary (1024)
Kibibyte	0.9765625 KiB
Mebibyte	0.0009536743164 MiB
Gibibyte	9.313225746 × 10⁻⁷ GiB
Tebibyte	9.094947018 × 10⁻¹⁰ TiB
Pebibyte	8.881784197 × 10⁻¹³ PiB

Converts data sizes between bits and bytes, the decimal units — kB, MB, GB, TB and PB — and the binary ones — KiB, MiB, GiB, TiB and PiB — plus kilobits, megabits and gigabits. One entry shows the result, the formula behind it and the same size in every other unit.

How to use it

Type a value and choose the units to convert from and to. The pickers accept gigs, bytes and other common spellings. Case tells bits from bytes: Mb is the megabit and MB the megabyte. KB is read as the decimal kilobyte of 1000 bytes, with a note beside the result; choose KiB for 1024.

Precision is Auto (up to 10 significant figures, and every whole-number digit) or Fixed (0 to 10 decimal places), and applies to the result and the table alike. Sizes cannot be negative.

Why a 1 TB drive shows 931 GB

Drive makers count in decimal units: a terabyte is a trillion bytes and a gigabyte a billion. The binary units count in powers of 1024 instead, so a gibibyte is 1,073,741,824 B and every step up the scale widens the gap.

A 1 TB drive is therefore 931.3225746 GiB, or 0.9094947018 TiB. Software that counts in binary units shows it as 931 GiB — or as 931 GB, where it keeps the decimal names for binary units. Nothing is missing. Formatting the drive takes some space on top of that.

A byte is 8 bits. The symbols tell them apart — b for bits, B for bytes — so a gigabit is 125 MB.

GiB = TB ÷ 0.001073741824

GiB = GB ÷ 1.073741824

MB = MiB × 1.048576

bit = B × 8

Examples

A 1 TB drive

1 TB is 931.3225746 GiB. Formula: GiB = TB ÷ 0.001073741824.

A file size in MiB

700 MiB is 734.0032 MB. Formula: MB = MiB × 1.048576.

Gigabits to megabytes

8 Gbit is 1,000 MB. Formula: MB = Gbit × 125.

Conversion tables

Drive sizes in binary units

Sold as	GiB	TiB
128 GB	119.2092896	0.1164153218
256 GB	238.4185791	0.2328306437
500 GB	465.6612873	0.4547473509
512 GB	476.8371582	0.4656612873
1 TB	931.3225746	0.9094947018
2 TB	1,862.645149	1.818989404
4 TB	3,725.290298	3.637978807
8 TB	7,450.580597	7.275957614
16 TB	14,901.16119	14.55191523

Decimal and binary units

Binary unit	Decimal unit	1 binary unit is
KiB	kB	1.024 kB
MiB	MB	1.048576 MB
GiB	GB	1.073741824 GB
TiB	TB	1.099511628 TB
PiB	PB	1.125899907 PB

Definitions and sources

The decimal prefixes are the SI ones, counting in thousands. The binary prefixes — kibi, mebi, gibi, tebi and pebi — were standardised by the IEC to count in powers of 1024, so that kilo, mega and giga keep their decimal meaning. Storage makers state capacity in decimal units, while some operating systems and apps report it in binary ones.

Sources

Definitions of the SI units: the binary prefixes — NIST
How storage capacity is measured on Apple devices — Apple

Reviewed 3 October 2026