Convert GB to MB instantly – no maths needed
Type in any number of gigabytes and this converter gives you the exact megabyte value right away. Perfect for checking file sizes, storage limits, data plans, or just settling a quick argument about how many MB are in a gigabyte.
1 GB = 1,024 MB – that is the single most-searched fact on this page, and everything else flows from it.
Quick GB to MB conversion table
Use this table for the most common values. The formula is MB = GB × 1,024. To go the other way (MB to GB), use GB = MB ÷ 1,024.
| Gigabytes (GB) | Megabytes (MB) |
|---|---|
| 1 GB | 1,024 MB |
| 2 GB | 2,048 MB |
| 5 GB | 5,120 MB |
| 10 GB | 10,240 MB |
| 25 GB | 25,600 MB |
| 50 GB | 51,200 MB |
| 100 GB | 102,400 MB |
How to use this GB to MB calculator
- Find the converter at the top of the page.
- Make sure Gigabytes (GB) is selected as the "from" unit and Megabytes (MB) as the "to" unit.
- Type your number into the input box – decimals are fine (e.g.
1.5or0.25). - The result appears immediately. No button to press.
- Need to go the other way? Swap the units to convert MB back to GB.
Worked example – converting 4.5 GB to MB
Say you have a video file that is 4.5 GB and you need to know its size in megabytes – for a form that only accepts MB, for example.
- Start with 4.5 GB.
- Multiply by 1,024 (the number of MB in one GB).
4.5 × 1,024 = 4,608 MB
So 4.5 GB = 4,608 MB. Paste that into the converter above and you will see the same answer in a split second.
How the calculation works
Digital storage is counted in powers of 2. One kilobyte (KB) is 1,024 bytes, one megabyte is 1,024 KB, and one gigabyte is 1,024 MB. That 1,024 factor comes from 210 = 1,024.
The formula is straightforward:
Megabytes = Gigabytes × 1,024Going back from MB to GB:
Gigabytes = Megabytes ÷ 1,024Binary (1,024) vs decimal (1,000) – which is right?
Hard drives and phone storage are sometimes marketed using decimal units, where 1 GB = 1,000 MB. Operating systems (Windows, macOS, Linux) use the binary definition, where 1 GB = 1,024 MB. That is why a "500 GB" hard drive shows as roughly 465 GB in Windows – the same bytes, a different counting rule.
- Use 1,024 when reading file sizes inside your operating system or working with RAM and firmware.
- Use 1,000 when matching the spec sheet of a hard drive, SSD, or mobile data plan.
This converter uses the binary standard (1 GB = 1,024 MB), which matches how computers actually count memory and file sizes.
Other ways people ask this question
People phrase the same conversion many different ways. Here is how they all connect:
- "How many MB in a GB?" – 1,024 MB (binary) or 1,000 MB (decimal/marketing).
- "How many MB is 2 GB?" – 2,048 MB.
- "Convert gigabytes to megabytes" – same calculation, multiply by 1,024.
- "How big is 1 GB in MB?" – 1,024 MB.
- "Is 1 GB equal to 1000 MB or 1024 MB?" – 1,024 MB in binary (OS/RAM); 1,000 MB in decimal (drive marketing).
- "MB to GB converter" – just swap the units in the tool above and divide by 1,024 instead.
Quick tips and common mistakes
- Mixing up KB, MB, GB, and TB is easy. Remember: each step up is ×1,024. So 1 TB = 1,024 GB = 1,048,576 MB.
- Decimal trap: if a cloud storage plan says "15 GB" and you expect 15,360 MB free, you might only see ~15,000 MB because the provider counts in decimals. Always check which definition the service uses.
- Rounding errors: for small files (under 1 MB) you may also want to work in kilobytes (KB) for more precision.
- Data transfer speeds are usually in megabits per second (Mbps), not megabytes (MB). There are 8 bits in a byte, so 100 Mbps ÷ 8 = ~12.5 MB/s download speed.
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Use the converter above to get any GB-to-MB result in seconds – no calculator app needed.