Gigabytes to Megabytes (GB to MB)
With SI decimal prefixes, as used on drive boxes, data plans and macOS, 1 GB is exactly 1,000 MB, so multiply by 1,000: 2.5 GB is 2,500 MB. In binary units (IEC 80000-13, also set out by NIST), 1 GiB is 1,024 MiB, which is the figure RAM and Windows use. The converter shows the decimal value; the binary one is in the notes.
Formula
MB = GB × 1,000 (binary: MiB = GiB × 1,024)
Example: 1 gigabytes = 1,000 megabytes.
Gigabytes to Megabytes chart
| gigabytes | megabytes |
|---|---|
| 0.1 | 100 |
| 0.25 | 250 |
| 0.5 | 500 |
| 1 | 1,000 |
| 1.5 | 1,500 |
| 2 | 2,000 |
| 3 | 3,000 |
| 4 | 4,000 |
| 5 | 5,000 |
| 8 | 8,000 |
| 10 | 10,000 |
| 16 | 16,000 |
| 32 | 32,000 |
| 64 | 64,000 |
| 100 | 100,000 |
| 128 | 128,000 |
| 256 | 256,000 |
Good to know
Binary answer: multiply by 1,024. 4 GiB of RAM is 4,096 MiB, 8 GiB is 8,192 MiB and 16 GiB is 16,384 MiB — the numbers you see in BIOS screens and virtual-machine settings.
Data plans and downloads: 1.5 GB of mobile data is 1,500 MB. If a game update is listed as 3.2 GB, plan on 3,200 MB of download — your router or carrier counts in decimal units too.
Upload limits: a service with a '2 GB' upload cap may mean 2,000 MB or 2,048 MiB. If a file is right at the edge, leave a few percent of headroom.
Frequently asked questions
How many MB are in 1 GB?
1,000 MB in decimal SI units, or 1,024 MiB in 1 GiB in binary units.
How many MB is 1.5 GB?
1.5 GB is 1,500 MB (decimal) or 1,536 MiB (binary).
How many MB is 4 GB?
4 GB is 4,000 MB in decimal units; 4 GiB is 4,096 MiB.
Which one should I use?
Use 1,000 for storage capacity, network transfer and data plans; use 1,024 for RAM and for sizes shown by Windows.