In 1 gigabytes there are 1,000 megabytes. Meanwhile in 1 megabytes there are 0.001 gigabytes. Keep reading to learn more about each unit of measure and how they are calculated. Or just use the Megabytes to Gigabytes calculator above to convert any number.
* Values rounded to 6 decimal places for readability
To convert gigabytes (GB) to megabytes (MB), you need to know which system you’re using: decimal (SI) or binary. Storage makers often use decimal, while many operating systems report sizes in binary.
Decimal (SI) conversion (common on drive labels):
1 GB = 1,000 MB
MB = GB × 1,000
Example: 2 GB = 2 × 1,000 = 2,000 MB
Binary conversion (common in OS reporting):
1 GB = 1,024 MB
MB = GB × 1,024
Example: 2 GB = 2 × 1,024 = 2,048 MB
Tip: If your numbers don’t match what you see on your computer, it’s often because GB (decimal) and GiB/GB (binary) get mixed in labels and reports.
In decimal (base-10), 1 gigabyte (GB) = 1,000 megabytes (MB). This is the standard used by most storage makers and many internet plans.
In binary (base-2), 1 gigabyte often means 1 gibibyte (GiB) = 1,024 mebibytes (MiB). Some systems show storage this way.
It depends on the system being used.
Both are “right,” but they measure in different units.
These pairs look similar but mean different things.
MiB and GiB are more exact for binary-based systems.
Use the method that matches your source:
Example (decimal): 5 GB × 1,000 = 5,000 MB.
Using decimal units (common for storage plans and drive labels):
Using binary units (GiB to MiB):
Yes. A gigabyte is larger than a megabyte in both systems.
Your device may report space using binary units while the drive label uses decimal units. That gap makes the number look smaller.
Also, some space goes to file system setup and reserved areas. The drive still matches its labeled size under the maker’s decimal rules.
Most internet plans and mobile data limits use decimal units, so:
Speeds are also usually decimal (Mbps), which can add to the confusion when you compare downloads and file sizes.
Using decimal units:
Using binary units (if 0.5 GiB is meant):
No. They measure different things.
There are 8 bits in 1 byte, so a rough speed conversion is:
Example: 80 Mbps is about 10 MB/s under ideal conditions.
Use 1,000 when you’re dealing with:
Use 1,024 when you’re dealing with:
If the unit says GiB or MiB, use 1,024. If it says GB or MB, it often means 1,000.
The Calculate Box tool to convert gigabytes to megabytes uses the open source script Convert.js to convert units of measurement. To use this tool, simply type a gigabytes value in the box and have it instantly converted to megabytes.