Convert gigabytes to megabytes
One gigabyte (GB) equals 1000 megabytes (MB), so multiply gigabytes by 1000 to get megabytes.
How do you convert gigabytes to megabytes?
Is 1 GB 1000 MB or 1024 MB?
Both numbers are in circulation, and they belong to two different units. In the decimal SI sense used by drive makers, mobile carriers, macOS and iOS, 1 GB is 1,000 MB, or 1,000,000,000 bytes. The 1,024 figure belongs to the gibibyte: 1 GiB is 1,024 MiB, or 1,073,741,824 bytes. Windows still prints GB while counting in gibibytes, and that single labelling habit is the source of nearly all the confusion. This page converts decimal gigabytes, so here 1 GB is 1,000 MB.
Which system your own device uses
Storage manufacturers, network operators and app stores quote decimal units. Apple moved macOS to decimal reporting in Mac OS X 10.6 Snow Leopard and iOS reports the same way, so an Apple device's figures line up with the box. Windows File Explorer divides by 1,024 at every step while still writing KB, MB and GB, so the same file looks smaller there than in a decimal tool even though not a single byte has changed.
Why a 1 TB drive shows as 931 GB
A 1 TB drive holds 1,000,000,000,000 bytes, exactly as advertised. Windows divides that by 1,024 three times, arrives at 931.32, and writes GB after it. Nothing is missing and nothing is reserved by formatting; it is one quantity in two units. A 2 TB drive shows as 1,862.65 for the same reason, and the gap widens with every step up the ladder.
The IEC names that remove the ambiguity
IEC 80000-13 gives the binary multiples their own names and symbols: kibibyte (KiB) for 1,024 bytes, mebibyte (MiB) for 1,024 KiB and gibibyte (GiB) for 1,024 MiB. Linux tools, memory datasheets and a growing number of file managers use them. When a figure is written GiB you know it is binary; when it is written GB it is meant to be decimal, whatever the software behind it actually did.
MB is not Mb
Storage is counted in bytes and bandwidth in bits, and a byte is eight bits. A 100 Mbps connection therefore moves at most 12.5 MB per second, so a 1 GB file takes about 80 seconds at full rate rather than 10. Reading a lowercase b as an uppercase B is an eightfold error, and it is why download estimates so often come out wrong by roughly that much.
Decimal versus binary storage units
Decimal units use powers of 1,000 and are what capacities are sold in. The IEC binary units use powers of 1,024. The last column is the calculated gap between the two, which is why the same drive can carry two different numbers.
| Decimal unit | Bytes | Binary unit | Bytes | Binary larger by |
|---|---|---|---|---|
| Kilobyte (KB) | 1,000 | Kibibyte (KiB) | 1,024 | 2.40% |
| Megabyte (MB) | 1,000,000 | Mebibyte (MiB) | 1,048,576 | 4.86% |
| Gigabyte (GB) | 1,000,000,000 | Gibibyte (GiB) | 1,073,741,824 | 7.37% |
| Terabyte (TB) | 1,000,000,000,000 | Tebibyte (TiB) | 1,099,511,627,776 | 9.95% |
This table has a page of its own: Decimal versus binary storage units adds the full ladder up to the exabyte, plus what each advertised drive size reports, names every source, and is free to embed or republish with credit.
Sources
Gigabyte to megabyte conversion table
| Gigabytes | Megabytes | Megabytes | Gigabytes |
|---|---|---|---|
| 1 GB | 1000 MB | 1 MB | 0.001 GB |
| 2 GB | 2000 MB | 2 MB | 0.002 GB |
| 3 GB | 3000 MB | 3 MB | 0.003 GB |
| 5 GB | 5000 MB | 5 MB | 0.005 GB |
| 10 GB | 10000 MB | 10 MB | 0.01 GB |
| 20 GB | 20000 MB | 20 MB | 0.02 GB |
| 50 GB | 50000 MB | 50 MB | 0.05 GB |
| 100 GB | 100000 MB | 100 MB | 0.1 GB |
| 500 GB | 500000 MB | 500 MB | 0.5 GB |
| 1000 GB | 1000000 MB | 1000 MB | 1 GB |
Decimal gigabytes to megabytes conversion table
The exact decimal amounts people look up most often, worked out with the same factor the converter above uses. Every row is calculated, not rounded off a chart.
| Gigabytes | Megabytes |
|---|---|
| 0.1 GB | 100 MB |
| 0.15 GB | 150 MB |
| 0.2 GB | 200 MB |
| 0.25 GB | 250 MB |
| 0.3 GB | 300 MB |
| 0.33 GB | 330 MB |
| 0.35 GB | 350 MB |
| 0.4 GB | 400 MB |
| 0.45 GB | 450 MB |
| 0.5 GB | 500 MB |
| 0.55 GB | 550 MB |
| 0.6 GB | 600 MB |
| 0.65 GB | 650 MB |
| 0.67 GB | 670 MB |
| 0.7 GB | 700 MB |
| 0.75 GB | 750 MB |
| 0.8 GB | 800 MB |
| 0.85 GB | 850 MB |
| 0.9 GB | 900 MB |
| 0.95 GB | 950 MB |
| 1 GB | 1000 MB |
| 1.05 GB | 1050 MB |
| 1.1 GB | 1100 MB |
| 1.15 GB | 1150 MB |
| 1.2 GB | 1200 MB |
| 1.25 GB | 1250 MB |
| 1.3 GB | 1300 MB |
| 1.35 GB | 1350 MB |
| 1.4 GB | 1400 MB |
| 1.45 GB | 1450 MB |
| 1.5 GB | 1500 MB |
| 1.55 GB | 1550 MB |
| 1.6 GB | 1600 MB |
| 1.65 GB | 1650 MB |
| 1.7 GB | 1700 MB |
| 1.75 GB | 1750 MB |
| 1.8 GB | 1800 MB |
| 1.85 GB | 1850 MB |
| 1.9 GB | 1900 MB |
| 1.95 GB | 1950 MB |
| 2 GB | 2000 MB |
Megabytes back to gigabytes
The same conversion in reverse, for when you have the answer and need the question.
| Megabytes | Gigabytes |
|---|---|
| 1 MB | 0.001 GB |
| 10 MB | 0.01 GB |
| 50 MB | 0.05 GB |
| 100 MB | 0.1 GB |
| 250 MB | 0.25 GB |
| 500 MB | 0.5 GB |
| 512 MB | 0.512 GB |
| 750 MB | 0.75 GB |
| 1000 MB | 1 GB |
| 1024 MB | 1.024 GB |
| 2000 MB | 2 GB |
Where the gigabyte to megabyte factor comes from
- UnitGlide uses the decimal (SI) definition, the one drive manufacturers and network operators use: the prefix giga means 10⁹ and mega means 10⁶.
- One gigabyte is therefore 1 000 000 000 bytes and one megabyte is 1 000 000 bytes.
- Dividing the two gives 1 GB = 1000 MB exactly. megabytes = gigabytes × 1000, so 0.1 GB is 100 MB and 0.5 GB is 500 MB.
- The binary alternative is a different unit with a different name: 1 gibibyte (GiB) is 2³⁰ = 1 073 741 824 bytes, which is 1024 mebibytes (MiB).
Sources
To convert gigabytes to megabytes, multiply the number of gigabytes by 1000. One gigabyte equals 1000 megabytes, and one megabyte equals 0.001 gigabytes, so the relationship is fixed and exact. As a worked example, 10 GB comes to 10000 MB. Enter your own figure in the converter above to get an instant answer, or use the swap button to flip the direction. This is a digital storage conversion, and like every tool on UnitGlide it runs locally in your browser with no account or upload required. The table further down shows a range of common gigabyte values already worked out in megabytes, plus the reverse megabyte to gigabyte direction, which is handy for quick reference or double-checking a result by hand.
Gigabyte to megabyte in practice
Gigabytes to megabytes is a conversion people run against data caps, download sizes and cloud quotas, where the only real question is whether the counting is decimal or binary.
Everyday uses
Mobile data plans, video export sizes and backup estimates all sit in this range. A 4 GB film is 4,000 MB on the decimal scale that carriers and storefronts use, a 25 MB email limit is 0.025 GB, and a 1.5 GB game update is 1,500 MB. Knowing the two lets you work out how many photos, songs or minutes of video a given allowance will hold.
Rounding never enters into it
UnitGlide multiplies by a clean 1,000, so no rounding is needed at any size: 1.5 GB is exactly 1,500 MB, 0.1 GB is 100 MB and 12.75 GB is 12,750 MB. That makes the arithmetic a decimal shift you can do in your head, which is usually all a quota or an upload limit needs.
Planning around a data cap
Because streaming quality is quoted in megabits per second but allowances in gigabytes, this conversion is what tells you how long a plan lasts. Standard-definition video runs around 700 MB an hour and high-definition several times that, so a 10 GB cap is roughly fourteen hours of SD or a few of HD. Turning the GB allowance into MB per hour is how you avoid a mid-month cut-off.
Frequently asked questions
How many MB is 1 GB?
1 GB is 1,000 MB in decimal units, the system used by storage makers, carriers, macOS and iOS. If your software counts in binary the matching unit is the gibibyte, where 1 GiB is 1,024 MiB.
Is 1024 MB a gigabyte or a gibibyte?
1,024 MiB is exactly 1 GiB, which is 1,073,741,824 bytes. Software that labels that a GB is using the older, loose meaning of the prefix rather than the SI one.
Why does my phone or drive show less storage than advertised?
Part of it is the operating system and preinstalled files, and part is the unit. A decimal 128 GB is 119.21 GiB, so a device that counts in binary shows 119 where the box says 128. Apple devices report in decimal, so there the whole difference is software taking up space.
How many MB is 0.1 GB?
0.1 GB is 100 MB using the decimal (SI) definition, where 1 GB is 1000 MB. If your software counts in binary, 0.1 GiB is 102.4 MiB instead.
How many MB is 0.5 GB?
0.5 GB is 500 MB. Half of 1000 MB, since the decimal factor is a clean 1000.
How many megabytes are in a gigabyte?
One gigabyte equals 1000 megabytes. The ratio is constant, so you can multiply any number of gigabytes by 1000 to get megabytes.
What is the formula to convert gigabytes to megabytes?
Use megabytes = gigabytes × 1000. UnitGlide applies this exact formula for every value, so results stay accurate across the whole range.
How do I convert megabytes back to gigabytes?
Go the other way by using one megabyte equals 0.001 gigabytes. You can also press the swap button in the converter above to flip the direction in one click.
Is this gigabyte to megabyte converter accurate?
Yes. It uses internationally defined SI conversion factors, as maintained by the BIPM, and all math runs in your browser so nothing is rounded away on a server. For everyday use the displayed precision is more than enough.