Memory / Storage Converter
Convert between data storage units like Kilobytes, Megabytes, and Terabytes.
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About this tool
Convert between bits, nibbles, bytes and their multiples in two families. The decimal (SI) units kilo, mega, giga, tera and peta use powers of 1,000, so 1 kilobyte is 1,000 bytes; this is how drive makers and network speeds are labeled. The binary (IEC) units kibi, mebi, gibi, tebi and pebi (KiB, MiB, GiB, TiB, PiB) use powers of 1,024, so 1 KiB is 1,024 bytes and 1 GiB is 1,073,741,824 bytes; this is what operating systems like Windows usually display when they write GB. A byte is 8 bits and a nibble 4 bits. Capital B means bytes and lowercase b means bits, and the result is labeled with that symbol.
How to use it
- Type the value to convert.
- Choose the From and To units.
- Read the result, which updates as you type.
- Use Swap to reverse the units or Copy to copy the result.
Example
256 gigabyte to megabyte
256000 MB
Decimal vs binary units
The same prefix letter can mean two sizes. The tool lists both families so you can pick the one you need.
- kB vs KiB
- 1,000 bytes vs 1,024 bytes
- MB vs MiB
- 1,000,000 bytes vs 1,048,576 bytes
- GB vs GiB
- 1,000,000,000 bytes vs 1,073,741,824 bytes
- TB vs TiB
- 1,000,000,000,000 bytes vs 1,099,511,627,776 bytes
Why a 1 TB drive shows about 931 GB
Drive makers sell in decimal units, so 1 TB is 1,000,000,000,000 bytes. Windows divides by 1,024 three times but still writes GB, so the same drive shows about 931 GB (931 GiB). macOS uses decimal units and shows close to the full 1 TB.
The shortfall grows with each prefix: a binary-unit display shows about 2.3% less for kilo, 4.6% less for mega, 6.9% less for giga and 9.1% less for tera. Formatting and preinstalled files take a little more space on top of that.
Bits, bytes and download times
Connection speeds are quoted in bits per second (Mbps), file sizes in bytes (MB). Multiply the file size by 8 to get bits, then divide by the speed. This ignores protocol overhead, so real downloads are a little slower.
seconds = size in MB x 8 / speed in Mbps 500 MB at 100 Mbps: 500 x 8 / 100 = 40 seconds
Common problems
- My file size differs from what the OS shows
- Drive makers use 1,000-based units (GB) while many systems show 1,024-based ones. Convert from GB to GiB here: 1 GB is about 0.93 GiB.
- Mixing up bits and bytes
- Internet speeds are in bits (Mb), file sizes in bytes (MB). Divide megabits by 8 to get megabytes.
- KiB or MB: which one do I pick?
- Use KiB, MiB, GiB and TiB for 1,024-based sizes and kB, MB, GB and TB for 1,000-based sizes. They are listed after the SI units.
Frequently asked questions
How many MB are in a GB?
1,000 in decimal units. In binary units there are 1,024 MiB in a GiB. Choose the units in the menus to see either.
Is RAM measured in GB or GiB?
RAM sizes are binary, so an 8 GB memory module holds 8 GiB, which is 8,589,934,592 bytes. Convert from gibibyte to byte here to check.