MB to GB converter
This calculator converts MB to GB: 1 GB is 1,000 MB, so 2,500 MB is exactly 2.5 GB. KB, TB, bits, megabits and the binary units MiB and GiB convert instantly too – including the download time at your internet speed.
Example: Value 2,500 · from: Megabyte (MB) · to: Gigabyte (GB) · Transfer rate for download time 100 Mbit/s → Result: 2,500 MB = 2.5 GB. Source: NIST – Prefixes for binary multiples (kibi, mebi, gibi …). Updated: .
How it is calculated
MB to GB: the formula
GB = MB ÷ 1,000. In reverse, MB = GB × 1,000. In the International System of Units, kilo, mega, giga and tera are powers of 1,000.
- 2,500 MB = 2.5 GB
- 1,000 MB = 1 GB
- 1 TB = 1,000 GB = 1,000,000 MB
MB or MiB? Two ways of counting
Computers work internally in powers of two: 1 KiB is 1,024 bytes, 1 MiB is 1,024 KiB and 1 GiB is 1,024 MiB (IEC 80000-13). Makers of drives and mobile plans count in decimal instead. Windows still shows binary values with the suffix “GB”, while macOS has counted in decimal since version 10.6. That is why 500 GB on the box is about 465.7 GiB.
Bits and bytes
One byte is 8 bits. Internet speeds are usually given in megabits per second, file sizes in megabytes: MB/s = Mbit/s ÷ 8.
Download time
Time = data size ÷ speed. 2.5 GB at 100 Mbit/s (12.5 MB/s) takes 200 seconds, or 3 min 20 s.
Honest limits
The download time is an ideal figure without protocol overhead or line fluctuations; in practice it often takes a little longer. File systems also reserve space, so a formatted drive has less usable capacity.
Frequently asked questions
How many MB are in 1 GB?
1 GB is 1,000 MB. In the binary system, 1 GiB is exactly 1,024 MiB.
How do I convert MB to GB?
Divide the megabytes by 1,000: 4,500 MB ÷ 1,000 = 4.5 GB.
Why does Windows show fewer GB than the drive label?
The manufacturer counts in decimal (1 GB = 1,000,000,000 bytes), Windows in binary (1 GiB = 1,073,741,824 bytes) but still writes “GB”. A 500 GB drive becomes about 465 “GB”.
How many MB/s is 100 Mbit/s?
100 Mbit/s is 12.5 MB/s, because a byte has 8 bits.
What is the difference between MB and Mb?
MB means megabyte, Mb (or Mbit) means megabit. One megabyte is 8 megabits.
Sources and legal basis
- NIST – Prefixes for binary multiples (kibi, mebi, gibi …)
- BIPM – SI Brochure: SI prefixes (kilo = 10³, mega = 10⁶, giga = 10⁹, tera = 10¹²)
As of: · Editorial policy
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