Converters Megabytes to gigabytes
Convert megabytes to gigabytes in both the decimal (1000) and binary (1024) conventions, and see why your drive looks smaller than the box said.
1 MB = 0.001 GB
gigabytes = megabytes × 0.001
megabytes to gigabytes
| MB | GB |
|---|---|
| 1 | 0.001 |
| 2 | 0.002 |
| 3 | 0.003 |
| 4 | 0.004 |
| 5 | 0.005 |
| 10 | 0.01 |
| 15 | 0.015 |
| 20 | 0.02 |
| 25 | 0.025 |
| 50 | 0.05 |
| 75 | 0.075 |
| 100 | 0.1 |
| 500 | 0.5 |
| 1,000 | 1 |
One megabyte is exactly 0.001 gigabytes.
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Cite this page
Reembun. (2026, July 28). Megabytes to gigabytes. https://reembun.com/convert/data/mb-to-gb
How to use it
Type the megabytes
Gigabytes appear immediately underneath.
Know which convention you need
This is the decimal convention, where a gigabyte is 1000 megabytes. The binary units are in the list if you are matching a figure Windows gave you.
Copy it or read the table
The table lists the sizes that appear in phone plans and storage tiers, already converted.
The two conventions
There are two ways to divide digital storage, and both are legitimate:
Decimal (SI) 1 GB = 1000 MB = 1,000,000,000 bytes
Binary (IEC) 1 GiB = 1024 MiB = 1,073,741,824 bytesThe binary convention exists because computers address memory in powers of two. The decimal convention exists because every other SI prefix means a power of ten. Neither side gave way, so both survive, and the gap between them grows with scale.
| Unit | Decimal bytes | Binary bytes | Difference |
|---|---|---|---|
| 1 kB / KiB | 1,000 | 1,024 | 2.4% |
| 1 MB / MiB | 1,000,000 | 1,048,576 | 4.9% |
| 1 GB / GiB | 1,000,000,000 | 1,073,741,824 | 7.4% |
| 1 TB / TiB | 10¹² | 1,099,511,627,776 | 10.0% |
Quick reference
| MB | GB (decimal) |
|---|---|
| 100 | 0.1 |
| 500 | 0.5 |
| 1,000 | 1 |
| 2,048 | 2.048 |
| 5,000 | 5 |
| 10,000 | 10 |
| 51,200 | 51.2 |
Where each convention appears
Decimal is used by hard drive and SSD manufacturers, by network speeds, by macOS since 10.6, and by most Linux tooling that reports SI units.
Binary is used by Windows Explorer, by RAM capacities (which are genuinely powers of two for addressing reasons), and by most older utilities.
This means the same drive can honestly be described as both 1 TB and 931 GB depending on who is counting. Nobody is lying; they are using different units with confusingly similar names.
Practical consequences
Buying storage. Budget roughly 7% more decimal capacity than the binary figure you need. A system that needs 500 GiB of usable space wants a 537 GB drive or larger.
Estimating download times. Divide a megabit figure by eight to get megabytes, then account for overhead. A 100 Mbps line moves about 12.5 MB/s in theory and typically 10-11 MB/s in practice.
Cloud storage quotas. Providers vary. Most consumer services quote decimal; check before assuming a 15 GB allowance holds 15 GiB of files.
Common questions
Is 1 GB 1000 MB or 1024 MB?
Both answers are in use, which is the whole problem. Storage manufacturers and network speeds use the decimal convention where 1 GB is 1000 MB. Windows and most operating systems report the binary convention where the same amount of storage divides by 1024. The IEC names the binary units separately, as kibibyte, mebibyte and gibibyte, but almost nobody outside standards documents writes GiB.
Why does my 1 TB drive show as 931 GB?
Because the manufacturer sold you 1,000,000,000,000 decimal bytes and your operating system divided by 1024 three times. 10 to the 12th over 1024 cubed is 931.32, so nothing is missing. The two are simply counting in different bases. This is also why the gap widens with capacity: it is about 7.4% at every scale.
What about megabits versus megabytes?
A byte is eight bits, and internet speeds are quoted in megabits per second while file sizes are in megabytes. A 100 Mbps connection therefore downloads at roughly 12.5 MB/s at best. Confusing the two makes a connection look eight times slower than advertised, which is the source of a great many complaints to ISPs.
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