Megabytes to Gigabytes (MB to GB)
Under the SI prefixes that storage makers, phone carriers and macOS use, a gigabyte is 1,000 megabytes, so divide MB by 1,000: 2,500 MB is 2.5 GB. Windows and RAM sizes count in powers of two, where 1 GiB = 1,024 MiB (IEC 80000-13; NIST's reference on prefixes for binary multiples). This converter uses the decimal SI value; the notes give the binary one.
Formula
GB = MB ÷ 1,000 (binary: GiB = MiB ÷ 1,024)
Example: 100 megabytes = 0.1 gigabytes.
Megabytes to Gigabytes chart
| megabytes | gigabytes |
|---|---|
| 1 | 0.001 |
| 10 | 0.01 |
| 50 | 0.05 |
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 750 | 0.75 |
| 1,000 | 1 |
| 1,024 | 1.024 |
| 1,500 | 1.5 |
| 2,000 | 2 |
| 2,048 | 2.048 |
| 4,096 | 4.096 |
| 5,000 | 5 |
| 8,192 | 8.192 |
| 10,000 | 10 |
| 16,384 | 16.384 |
Good to know
Decimal or binary? The SI prefix mega means 10⁶ and giga 10⁹, so 1 GB = 1,000 MB. In 1998 the IEC added the binary prefixes kibi, mebi and gibi so that 1 GiB = 1,024 MiB = 1,073,741,824 bytes. Windows File Explorer still labels GiB as 'GB', which is why the same file can show a slightly different size on a PC and a Mac.
Binary answer: divide by 1,024 instead. 500 MiB is 0.488 GiB, 2,048 MiB is exactly 2 GiB and 8,192 MiB (a typical 8 GB RAM figure) is 8 GiB. The difference between the two answers is 2.4% at this step.
Mobile data: carriers bill in decimal gigabytes. If an app says it used 750 MB, that is 0.75 GB of your plan; 4,500 MB of hotspot use is 4.5 GB.
Frequently asked questions
Is 1 GB 1,000 MB or 1,024 MB?
Both are in use. In SI decimal units (drives, data plans, macOS) 1 GB = 1,000 MB. In binary units (RAM, Windows) 1 GiB = 1,024 MiB, often still written 'GB'.
How many GB is 500 MB?
500 MB is 0.5 GB in decimal units, or 0.488 GiB in binary.
How many GB is 2,048 MB?
2,048 MB is 2.048 GB in decimal units, or exactly 2 GiB in binary.
Why does my file look smaller in Windows?
Windows divides by 1,024 at each step but still shows 'MB' and 'GB'. A 5,000,000,000-byte file is 5 GB on a Mac and 4.66 'GB' (GiB) in Windows.