GB to MB Converter - Convert GigaBytes to MegaBytes (2024)

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1. How many MegaBytes equal one GigaByte?
2. Difference between GB and MB
3. How to convert GigaBytes to MegaBytes
4. GB to MB conversion table

How many MegaBytes equal one GigaByte?

There are two competing definitions for the gigabyte. According to the binary definition, in which each metric is a power of two, a gigabyte is exactly 1024 megabytes. According to the SI and IEC standard, which is in use in organizations such as the IEEE, EU, ISO, NIST, but is still not widely accepted, 1 gigabyte equals 1000 megabytes. It should be noted that a megabyte in the first definition is also defined differently to that of the second definition, making the difference even larger than it seems at first glance.

For example, maybe you have recently bought a 4 TB disk drive, or a 256 GB SSD? Do not be surprised then when your 4 TB drive actually holds 3.63 TB of data and your 256 GB SSD actually holds 231 GB of data, as shown by your Windows operating system, for example. The reason is that the definition used by disk manufacturers is the SI definition and the one used by most operating systems is the standard binary definition. Which one makes more sense: the one where mega is one million and giga is one billion (SI), or the one where the size of RAM is always accurately rounded, e.g. there is no 1 GB (SI) RAM, but there is exactly 1 GB (binary) RAM? Opinions go both ways while the confusion continues decade after decade among experts in computer science and end users alike.

The SI and IEC adopted a new metric to replace the traditional gigabyte: Gibibyte. Its symbold is GiB. However, we challenge you to find someone who is not working as a developer for disk drivers who has heard of or is actually using this name.

Difference between GB and MB

Both GB and MB are symbols corresponding to units for measuring data storage on devices such as hard drives, solid state drives, CD-ROMs, DVDs, etc. The difference between them is only in their magnitude, where the GB is defined as containing 1024 MB under the binary definition and 1000 MB under the International System of Units.

One often needs to convert from gigabytes to megabytes when calculating storage capacity, e.g. for video files from surveillance cameras, or for your personal video or audio collection. In any case, it is important to make sure that the units advertised are the same units you perform the calculations in - in our GB to MB converter you can switch between units using the SI checkbox below the input fields.

How to convert GigaBytes to MegaBytes

Performing conversions between GB and MB is easy, once you know the standard you want to use. Under SI it is easier as you need to only multiply by 1,000, or - just move the decimal point three positions to the right. Under the binary system you multiply by 1024 to get the megabyte equivalent. See some practical examples with calculations below:

GB to MB conversion example

Sample task: convert 128 gigabytes to megabytes (binary, also GiB to MiB). Solution:

Formula:
GB * 1024 = MB
Calculation:
128 GB * 1,024 = 131,072 MB
End result:
128 GB is equal to 131,072 MB

Sample task: convert 100 gigabytes to megabytes (SI). Solution:

Formula:
GB * 1000 = MB
Calculation:
100 GB * 1,000 = 100,000 MB
End result:
100 GB is equal to 100,000 MB

GB to MB conversion table