MB to GB: Megabytes to Gigabytes Converter
Both conventions, with the gap between them shown rather than hidden.
Enter a number.
Free · No sign-up · Updates as you type · Factors from NIST
- 100 MB0.100 GB0.098 GiB
- 500 MB0.500 GB0.488 GiB
- 1,000 MB1.000 GB0.977 GiB
- 1,024 MB1.024 GB1.000 GiB
- 2,000 MB2.000 GB1.953 GiB
- 4,096 MB4.096 GB4.000 GiB
- 8,192 MB8.192 GB8.000 GiB
- 16,000 MB16.000 GB15.625 GiB
- 32,000 MB32.000 GB31.250 GiB
Your drive and your operating system are counting differently. The manufacturer sold you a decimal gigabyte of 1,000,000,000 bytes. Your file manager is almost certainly dividing by 1,024 three times and reporting a smaller number. Neither is lying, and neither usually says which convention it is using. This tool makes you pick, and defaults to decimal because that is what capacity is sold in.
Why a new drive looks smaller than the box
A drive sold as 32 GB contains 32 billion bytes. Your operating system divides that by 1,024 three times, to get from bytes to kilobytes to megabytes to gigabytes, and reports roughly 29.8. The drive isn't short; the two sides are counting differently.
32,000,000,000 bytes ÷ 1024³ = 29.80 GB (binary)
The gap compounds at each step, measured from bytes: about 2.4 percent at the kilobyte, 4.9 percent at the megabyte, 7.4 percent at the gigabyte and 10.0 percent at the terabyte.
Conversion table
| Megabytes | GB (decimal) | GB (binary) | Common context |
|---|---|---|---|
| 500 MB | 0.500 | 0.488 | CD-ROM |
| 1,000 MB | 1.000 | 0.977 | 1 GB as sold |
| 1,024 MB | 1.024 | 1.000 | 1 GiB as reported |
| 4,096 MB | 4.096 | 4.000 | 4 GB memory module |
| 8,192 MB | 8.192 | 8.000 | 8 GB memory module |
| 16,000 MB | 16.000 | 15.625 | 16 GB as sold |
| 32,000 MB | 32.000 | 31.250 | 32 GB as sold |
| 64,000 MB | 64.000 | 62.500 | 64 GB as sold |
Formatting takes some too
Separately from the counting convention, a filesystem reserves space for its own structures, so usable capacity is a little below raw capacity. That is a real reduction rather than an arithmetic one, and it is usually small compared with the decimal-versus-binary gap.
Common questions
Is 1 GB 1000 MB or 1024 MB?
1,000 under the decimal convention used by manufacturers, 1,024 under the binary convention used by most operating systems. This tool shows both.
Why does my 32 GB drive show as 29.8 GB?
Because it holds 32 billion bytes, which the manufacturer counts as 32 GB decimal, while your operating system divides by 1,024 three times and reports about 29.8. Nothing is missing.
How many MB in a GB?
1,000 decimal or 1,024 binary. The difference is 2.4 percent at this step and compounds at each further step.
Which does my phone use?
Most operating systems report binary while advertising decimal, which is why reported free space rarely matches the box.
Related converters and guides
Sources
- The binary prefixes kibi, mebi and gibi are defined by the International Electrotechnical Commission, not by the SI. The decimal prefixes kilo, mega and giga are SI and are always powers of 1,000. That split is the source of the disagreement described on this page.
- NIST Guide to the SI, Appendix B: Conversion Factors. National Institute of Standards and Technology. Source for every conversion factor on this page, and for which factors are exact rather than rounded.