💾 MB to GB Converter
Convert megabytes to gigabytes and back. The exact factor, a table of the values people look up most, and what each unit is actually used for.
Converting megabytes to gigabytes
One megabyte is 0.001 gigabytes, and one gigabyte is 1000 megabytes.
gigabytes = megabytes × 0.001
Getting the precision right
In decimal, 1 GB is 1,000 MB. In binary, which Windows still uses when it writes GB, 1 GB is 1,024 MB. The gap compounds: a 1 TB drive advertised in decimal shows as about 931 GB in Windows, and nothing is missing — the two are counting differently. The unambiguous binary units are MiB and GiB, which macOS and most Linux systems now use correctly.
Where each unit is used
Mobile data allowances, file sizes and storage capacities all mix the two, and the industry is inconsistent about what they mean. Storage manufacturers use decimal units while operating systems have historically used binary ones, which is why a new drive always looks smaller than advertised.
Values worth knowing
| MB | GB |
|---|---|
| 100 | 0.1 |
| 250 | 0.25 |
| 500 | 0.5 |
| 1000 | 1 |
| 1024 | 1.024 |
| 2000 | 2 |
| 5000 | 5 |
| 10000 | 10 |
| 50000 | 50 |
| 100000 | 100 |
A 500 MB file is 0.5 GB. A two-hour film in HD is roughly 4 GB. A 1 TB drive holds about 931 GiB as Windows reports it.
Where the two units came from
The ambiguity is an accident of hardware. Computer memory is addressed in powers of two, so a kilobyte of RAM naturally meant 1,024 bytes, and programmers adopted the metric prefixes loosely. Disk manufacturers, with no such constraint, used the metric meaning of 1,000. The binary prefixes kibi, mebi and gibi were standardised in 1998 to settle it, and most of the industry adopted them — except Windows, which still displays binary quantities under decimal names.
Round the result to the precision your own work needs. These converters carry the full factor, which is useful for checking but rarely what you want to write down.
If the number here raised another question, it is probably one of these: the kg to lbs or the lbs to stone.
Frequently Asked Questions (FAQs)
How many MB are in a GB?
1,000 in decimal units, which is what storage manufacturers and mobile operators use. 1,024 in binary units, which is what Windows means when it writes GB. Both answers are correct under their own convention.
Why does my 1 TB drive show as 931 GB?
Because the manufacturer counted in decimal, where a terabyte is a trillion bytes, and Windows displays binary gigabytes of 1,073,741,824 bytes each. The drive holds exactly what was advertised; the two systems are labelling the same bytes differently.
What are MiB and GiB?
The unambiguous binary units: a MiB is 1,048,576 bytes and a GiB is 1,024 MiB. They were introduced precisely to end this confusion, and most Linux and macOS tools now use them correctly while Windows does not.