MB to GB: How Many MB Are in a GB?

By the Tool Goodie Team · Updated July 4, 2026 · 4 min read

There are 1,024 megabytes (MB) in a gigabyte (GB) using the binary convention that computers use — or 1,000 MB using the decimal convention that storage makers use. To convert MB to GB, divide by 1,024 (or 1,000); to go from GB to MB, multiply. Below is why there are two answers, and why your new drive always shows less space than the box promised.

Key takeaways

MB → GB: divide by 1,024 (binary) or 1,000 (decimal).
Operating systems use 1,024; storage manufacturers use 1,000.
That mismatch is why a "1 TB" drive shows as ~931 GB.
Convert any size with the data storage converter.

The two conventions

Digital storage can be measured two ways, and both are in common use:

Binary (base 2): 1 GB = 1,024 MB, 1 MB = 1,024 KB. This is how operating systems (Windows, macOS, Android) report file sizes and free space.
Decimal (base 10): 1 GB = 1,000 MB. This is what hard-drive, SSD, and phone manufacturers use on the box.

Strictly, the binary units have their own names — kibibyte (KiB), mebibyte (MiB), gibibyte (GiB) — but almost nobody uses them in everyday speech, so "MB" and "GB" mean different things depending on who's counting.

MB to GB table

Megabytes	Gigabytes (binary, ÷1024)
512 MB	0.5 GB
1,024 MB	1 GB
2,048 MB	2 GB
5,120 MB	5 GB
10,240 MB	10 GB

Convert instantly: the free Data Storage Converter handles bits, bytes, KB, MB, GB and TB — type a value and read the answer immediately.

Why your drive shows less than advertised

This is the classic confusion. A manufacturer sells you a "1 TB" drive, meaning 1,000,000,000,000 bytes (decimal). Your operating system then divides by 1,024 three times to display gigabytes, giving about 931 GB. No storage has vanished — the drive really holds a trillion bytes — it's just labeled in decimal and displayed in binary. The bigger the drive, the bigger the apparent "gap."

MB vs Mbps: a common mix-up

Don't confuse MB (megabytes, a measure of size) with Mbps (megabits per second, a measure of internet speed). There are 8 bits in a byte, so a 100 Mbps connection downloads at roughly 12.5 MB per second. That factor of 8 is why a file downloads slower than the headline speed number suggests.

Frequently asked questions

How many MB are in a GB?

There are 1024 megabytes in a gigabyte using the binary convention that operating systems use, or 1000 using the decimal convention that storage makers use. To convert MB to GB, divide by 1024 (or 1000).

Why does my hard drive show less space than advertised?

Manufacturers measure capacity in decimal units (1 GB = 1000 MB), while your operating system reports it in binary units (1 GB = 1024 MB). A "1 TB" drive therefore shows as about 931 GB — no space is missing, it's just measured two different ways.

What is the difference between MB and Mbps?

MB (megabytes) measures file size or storage, while Mbps (megabits per second) measures internet speed. There are 8 bits in a byte, so a 100 Mbps connection downloads at roughly 12.5 MB per second.