Data Storage Converter
Convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes, and petabytes.
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How to use this calculator
- 1
Enter the data size value you want to convert.
- 2
Select the unit you are converting from (e.g. gigabytes).
- 3
Select the target unit (e.g. megabytes).
- 4
The result is calculated instantly.
Frequently asked questions
What is the difference between a kilobyte and a kibibyte?
A kilobyte (kB) is 1,000 bytes under the SI prefix system, while a kibibyte (KiB) is 1,024 bytes (2^10) under the IEC binary system. The converter keeps them apart: 1 KiB is 1.024 kB, 1 MiB is 1.048576 MB and 1 GiB is 1.073741824 GB. Mixing them causes the familiar gap between advertised and displayed sizes.
Why does a 1 TB drive show about 931 GB?
Drive makers use decimal units, so 1 TB is 1,000,000,000,000 bytes. Many operating systems count in binary, where that is 931.3225746 GiB. Nothing is missing: it is the same number of bytes expressed in a larger unit, a figure about 6.9 percent below the 1,000 GB on the box.
Which operating systems use which units?
Windows has traditionally reported sizes in binary multiples but labelled them KB, MB and GB, so a 1 TB drive reads about 931 GB there. macOS reports decimal units, so the same drive reads 1 TB. The converter lets you check either reading.
How many bits are in a byte?
Eight. The tool treats the lowercase bit and uppercase byte as different units, so 1 B is 8 bits and 1 GB is 8,000,000,000 bits. Network speeds are quoted in bits, while file sizes are quoted in bytes, which is why the data transfer converter exists.
How big is a 4.7 GB disc in binary units?
4.7 GB is 4,700,000,000 bytes, which is 4.377216101 GiB or 4,482.269287 MiB. Disc and flash sizes are often given in decimal units, so the binary figure that a computer reports is smaller.
Is RAM measured in decimal or binary?
Memory is built in powers of two, so 16 GB of RAM is normally 16 GiB, which is 17.179869184 GB in decimal. Storage devices sold by decimal capacity, such as drives and cards, behave the other way.
Does it account for file system overhead or compression?
No. It converts one size unit to another by pure arithmetic. A formatted disk offers less usable space than its raw capacity, and compressed files occupy less than their original size; neither effect is modelled.
Data storage units: bits, bytes, decimal and binary prefixes
Two prefix systems, two sets of numbers
Kilobyte, megabyte, gigabyte, terabyte and petabyte are SI decimal units: 1 kB is 1,000 B, 1 MB is 1,000,000 B and 1 GB is 1,000,000,000 B. Kibibyte, mebibyte, gibibyte and tebibyte are binary units defined by powers of 1,024: 1 KiB is 1,024 B, 1 MiB is 1,048,576 B and 1 GiB is 1,073,741,824 B. The converter keeps both sets with their exact values, and one byte is always 8 bits. The differences compound with each step: 1 KiB is 2.4 percent above 1 kB, and 1 TiB is about 10 percent above 1 TB (1.099511628 TB).
Decimal units in binary terms
This table starts from decimal sizes and shows the same number of bytes in binary units, copied from the converter’s output.
| From | Bytes | KiB | MiB | GiB |
|---|---|---|---|---|
| 1 MB | 1,000,000 | 976.5625 | 0.95367432 | 0.00093132257 |
| 1 GB | 1,000,000,000 | 976,562.5 | 953.6743164 | 0.93132257 |
| 1 TB | 1,000,000,000,000 | 976,562,500 | 953,674.316406 | 931.3225746 |
| 1 PB | 1,000,000,000,000,000 | 976,562,500,000 | 953,674,316.40625 | 931,322.574615 |
Binary units in decimal terms
The reverse view starts from binary sizes. Each is larger than its decimal namesake by a growing margin.
| From | Bytes | kB | MB | GB |
|---|---|---|---|---|
| 1 KiB | 1,024 | 1.024 | 0.001024 | 0.000001024 |
| 1 MiB | 1,048,576 | 1,048.576 | 1.048576 | 0.001048576 |
| 1 GiB | 1,073,741,824 | 1,073,741.824 | 1,073.741824 | 1.073741824 |
| 1 TiB | 1,099,511,627,776 | 1,099,511,627.776 | 1,099,511.627776 | 1,099.511628 |
Worked examples: drives and discs
A 1 TB drive holds 931.3225746 GiB, a figure 6.9 percent lower than the 1,000 GB printed on the box. A 512 GB drive is 476.8371582 GiB, and a 256 GB card is 238.4185791 GiB. A 4.7 GB disc is 4.377216101 GiB. At the small end, 1 GB is 8,000,000,000 bits. The same logic applies to phones and memory cards, where the stated capacity is decimal and the operating system may report a smaller number in GiB. A 256 GB card shows 238.4185791 GiB, which is not a defect.
What the tool does not cover
The list has no kilobit or megabit entries, and it does not model file system overhead, partitions or compression. For speeds in bits per second, use the data transfer converter. Ten significant digits is a display choice, not a claim about how big your files really are. For a rough estimate, divide a decimal GB figure by 1.0737 to reach GiB, or multiply a GiB figure by the same amount to reach GB. The converter performs the exact arithmetic for you, so you do not need to remember either factor. Remember, too, that a bit is lowercase b and a byte uppercase B in every unit label on the page.
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Results are estimates for informational purposes only and do not constitute professional financial, medical, legal, or technical advice. Read full disclaimer →