Convert MB to GB, Free
Type any MB value and see the GB result instantly. No button press needed.
How to convert MB to GB
There are two competing definitions for what a gigabyte means, and the difference matters when reading storage device specs. In the decimal system (SI), 1 GB = 1,000 MB = 1,000,000,000 bytes, which is what hard drive manufacturers use when labeling drive capacity. In the binary system used by operating systems, 1 GiB = 1,024 MiB = 1,073,741,824 bytes. This is why a hard drive labeled 500 GB shows up as about 465 GB in Windows or macOS.
This converter handles both definitions. By default it uses the decimal definition (1,000 MB per GB) that matches what storage manufacturers print on boxes. Switch to binary mode if you are working with RAM specifications or reading OS-reported disk usage. The calculation runs instantly in your browser with no data sent anywhere.
Select decimal or binary mode
Choose decimal (1 GB = 1,000 MB) for storage device specs and file transfer measurements. Choose binary (1 GiB = 1,024 MiB) for RAM specs and operating system disk reporting.
Enter the MB value
Type the number of megabytes to convert. For example, 2,048 MB converts to 2.048 GB (decimal) or 2 GiB (binary).
Read the GB result
The result appears instantly. The formula is: GB = MB / 1,000 (decimal) or GiB = MiB / 1,024 (binary).
Understand the context
If you are comparing a drive's advertised capacity to what your OS reports, convert using both modes to see why the numbers differ.
Frequently asked questions
Why does my 1 TB hard drive show as 931 GB in Windows?
The manufacturer labels the drive using decimal gigabytes (1,000 MB each). Windows reports storage using binary gibibytes (1,024 MiB each). 1,000,000 MB / 1024 / 1024 = 931 GiB. Both numbers describe the same drive; they just use different unit definitions.
What does MB actually stand for?
MB stands for megabyte. In the decimal system, 1 megabyte = 1,000,000 bytes. In the binary system, 1 mebibyte (MiB) = 1,048,576 bytes. The term megabyte has historically been used for both, which is the root of the confusion.
How many MB is a typical MP3 song?
A 4-minute song at 128 kbps is about 3.8 MB. At 320 kbps it is about 9.4 MB. Using the decimal definition, 1 GB would hold roughly 263 songs at 128 kbps.
Is RAM measured in binary or decimal gigabytes?
RAM is specified in binary. 4 GB of RAM is 4 x 1,073,741,824 bytes = 4,294,967,296 bytes. Your operating system will report this correctly as 4 GB (using the binary definition implicitly).