How GB to MB conversion works
A gigabyte is larger than a megabyte by a factor of 1024 in the binary system used by operating systems for RAM and file sizes: 1 GB = 1024 MB. So multiply the number of gigabytes by 1024. For 2 GB: 2 × 1024 = 2048 MB.
A worked example: a 16 GB memory stick is 16,384 MB by this maths, and a 250 MB app update is roughly 0.24 GB.
The bits to bytes calculator handles the closely related case.
Binary vs decimal (1024 vs 1000)
Storage makers often use the decimal (SI) convention where 1 GB = 1000 MB, which is why a "500 GB" drive shows less in your operating system. This calculator uses the binary 1024 factor. To convert back, use the megabytes to gigabytes calculator.
The gap widens as the numbers grow. A drive sold as 500 GB holds 500,000,000,000 bytes, which your operating system reports as about 465 GB - a shortfall of roughly 7%. At the terabyte scale that difference reaches about 9%, so a 2 TB drive shows around 1.82 TB. Nothing is missing; the two sides are just counting in different bases.
GB to MB reference table
Common conversions (1024 factor):
| Gigabytes | Megabytes |
|---|---|
| 0.5 GB | 512 MB |
| 1 GB | 1024 MB |
| 2 GB | 2048 MB |
| 4 GB | 4096 MB |
| 16 GB | 16384 MB |
Working with smaller units? See the bytes to bits calculator.
Everything is calculated in your browser, so no value you enter is uploaded or stored. Decimal inputs work too, which is handy for mobile data plans: 0.75 GB of a monthly allowance is 768 MB, and a 1.5 GB video download is 1536 MB.
Frequently asked questions
- How many MB are in 2 GB?
- 2048 MB, using the binary factor of 1024 MB per GB.
- Is 1 GB 1000 or 1024 MB?
- Operating systems use 1024 (binary). Drive manufacturers often use 1000 (decimal/SI), which is why advertised capacity looks larger.
- How do I convert GB to MB?
- Multiply the number of gigabytes by 1024. For example 4 GB × 1024 = 4096 MB.
- Why does my drive show less space than advertised?
- Manufacturers count 1 GB as 1000 MB, but your system counts 1024, so the same drive reports fewer gigabytes.
- Are GiB and MiB the same as the values shown here?
- Yes. This calculator uses the 1024 factor, which the IEC formally names GiB and MiB. Most operating systems display exactly these numbers but still label them GB and MB, which is where the confusion starts.