Data Storage Converter
Convert a file or disk size between bits, bytes, decimal units (kB, MB, GB, TB, PB) and binary units (KiB, MiB, GiB, TiB, PiB), and see why a drive looks smaller than its label.
Result…
How it's calculated
1 byte = 8 bits Decimal: 1 kB = 1000 B, 1 MB = 1000² B, 1 GB = 1000³ B, 1 TB = 1000⁴ B, 1 PB = 1000⁵ B Binary: 1 KiB = 1024 B, 1 MiB = 1024² B, 1 GiB = 1024³ B, 1 TiB = 1024⁴ B, 1 PiB = 1024⁵ B
Computer sizes have two sets of units. The SI prefixes kilo, mega, giga, tera and peta mean powers of 1000, so a 1 TB drive holds 1,000,000,000,000 bytes. Because memory is built in powers of two, programmers long used the same names for powers of 1024. To end the clash, the International Electrotechnical Commission approved separate binary prefixes in December 1998: kibi (Ki, 2¹⁰), mebi (Mi, 2²⁰), gibi (Gi, 2³⁰), tebi (Ti, 2⁴⁰) and pebi (Pi, 2⁵⁰), as listed by NIST. A lower-case b means bits, so network speeds in Mbit/s divide by 8 to give megabytes per second.
Your numbers, step by step
About the Data Storage Converter calculator
This data storage converter changes a file, memory or disk size between bits, bytes, decimal units (kB, MB, GB, TB, PB, steps of 1000) and binary units (KiB, MiB, GiB, TiB, PiB, steps of 1024). Enter one size and it gives the unit you pick, plus the size in bytes, bits and in every other unit in the steps. It is the quickest way to see why a drive sold as 500 GB shows up as about 465 in a program that counts in binary but still writes "GB". Nothing is missing: the two numbers use different units. The binary prefixes kibi, mebi and gibi were approved by the IEC in December 1998 to end the mix-up, as NIST explains. Network speeds are in bits, so it also turns Mbit or Gbit into bytes.
How to use it
- Enter the “Size”.
- Choose its unit under “From”, such as gigabytes (GB) or gibibytes (GiB).
- Choose the unit you want under “To”.
- Read the converted size, the bytes and bits, and the size in every unit in the steps.
Worked example
A 2 TB drive holds 2 × 1000⁴ = 2,000,000,000,000 bytes. In binary units that is 2,000,000,000,000 ÷ 1024⁴ = 1.819 TiB, which a program counting in binary may show as "1.82 TB". Likewise 500 GB is 465.66 GiB, and 1 GiB is 1.0737 GB.
Updated
Questions people ask
Is a kilobyte 1000 or 1024 bytes?
In SI units a kilobyte (kB) is 1000 bytes. 1024 bytes is a kibibyte (KiB). Older software and some systems still use KB to mean 1024, so check which one a figure uses.
Why does my new drive show less space than the box says?
Drive sizes are usually quoted in decimal units, while some operating systems count in binary units but label them GB or TB. A 1 TB drive is 0.909 TiB, and formatting takes a little more for the file system.
How many megabytes are in a gigabit?
One gigabit is 1,000,000,000 bits, and a byte is 8 bits, so it is 125 MB. A lower-case b means bits and an upper-case B means bytes.
How do I convert GB to GiB?
Multiply by 1000³ to get bytes, then divide by 1024³. That is the same as multiplying GB by 0.93132.
How long will a file of this size take to download?
That depends on the connection speed, which is usually given in bits per second. The download time calculator works it out from the size and the speed.