Data Size Converter
Convert a data size into steps of 1,000 (KB, MB, GB, TB) and steps of 1,024 (KiB, MiB, GiB, TiB) at the same time. Bits and bytes are included.
Steps of 1,000 vs. steps of 1,024
There are two families of data size units, which differ in the ratio between one unit and the next.
| Family | Units | Ratio to the next unit | Example |
|---|---|---|---|
| Steps of 1,000 (SI prefixes) | KB, MB, GB, TB | 1,000 | 1 KB = 1,000 bytes, 1 GB = 1,000 MB |
| Steps of 1,024 (IEC binary prefixes) | KiB, MiB, GiB, TiB | 1,024 | 1 KiB = 1,024 bytes, 1 GiB = 1,024 MiB |
Other relations:
- 1 byte = 8 bits
- The capacity printed on storage products such as hard disks, SSDs and USB drives usually uses steps of 1,000 (GB, TB).
- Some operating systems, including Windows, display sizes calculated in steps of 1,024 with the label "GB" (strictly, these are GiB).
This calculator always shows the results in both families.
Examples
- 1 GB = 1,000 MB = 1,000,000,000 bytes = about 0.9313 GiB
- 1 GiB = 1,024 MiB = 1,073,741,824 bytes = about 1.0737 GB
- 1 TB = about 0.9095 TiB = about 931.32 GiB
- 1 byte = 8 bits, and 1 bit = 0.125 bytes
When you connect a 1 TB hard disk to a computer, it may show about 931 GB. The capacity has not shrunk: a 1 TB disk in steps of 1,000 is displayed in steps of 1,024.
How it is calculated
- The size you enter is first converted to bytes (for example, 1 GiB = 1,024 × 1,024 × 1,024 bytes).
- The bytes are then divided by the size of each unit to get the value in every unit.
The calculation uses exact fractions with no rounding error. At the end, the values are rounded to 6 decimal places for display.
Source
The two families of prefixes follow Wikipedia, "Binary prefix": https://en.wikipedia.org/wiki/Binary_prefix (read on November 1, 2026; only the first part of that long page could be read word for word): the binary prefixes kibi, mebi and gibi mean 2^10 = 1,024, 2^20 and 2^30, and they were defined in 1999 by the International Electrotechnical Commission (IEC 60027-2) to replace the ambiguous use of kilo, mega and giga. It is an explanatory article, not a standard.
Things to know
- You can enter decimals (up to 12 digits before the decimal point and 6 decimal places). Thousands separators such as 1,234.5 are accepted; use a period as the decimal separator.
- When a value is so small that it rounds to 0 at 6 decimal places, "below 0.000001" is shown.
- Connection speeds (bps, Mbps and so on) are not converted here. For bitrates, see the Video Bitrate Calculator.
- To find a file size from a bitrate and a duration, use the Video File Size Calculator.
Frequently asked questions
How many MB are in a GB?
In steps of 1,000 (SI), 1 GB is 1,000 MB. In steps of 1,024, 1 GiB is 1,024 MiB. Some computers show the 1,024-based value with the label "GB", so you may see "1 GB = 1,024 MB" written.
What is the difference between GB and GiB?
1 GB is 1,000,000,000 bytes and 1 GiB is 1,073,741,824 bytes, so a GiB is about 7.4% larger. For TB and TiB, the difference is about 10%.
Why does a 1 TB hard disk show as 931 GB?
The capacity of the product is written in steps of 1,000 (1 TB = 1,000,000,000,000 bytes). The computer displays it in steps of 1,024, which gives about 931.
What is the difference between a bit and a byte?
1 byte is 8 bits. Connection speeds are usually written in bits (Mbps), and file sizes in bytes (MB), so be careful not to mix them up.