MB to GB converter, decimal and binary, side by side.

To convert MB to GB, divide by 1,000. So 500 MB is 0.5 GB, 2,500 MB is 2.5 GB and 10,000 MB is 10 GB. That is the decimal rule, where 1 GB is 1,000 MB. The binary rule divides by 1,024 and gives MiB to GiB: 2,560 MiB is 2.5 GiB. The tool shows both, because the word megabyte has been used for both.

How to use the converter

1. Type the size in the Megabytes (MB) box.
2. The big result shows Gigabytes (GB), counting 1,000 MB to the GB. The cards give Gibibytes, Mebibytes, terabytes and megabits for the same amount.
3. Type GB in the second box to get MB, or press S to swap.
4. Click a row in Common values to load it, then Copy result or Print chart.

Decimal: 1 GB is 1,000 MB

NIST, metric SI prefixes lists mega as 10⁶ and giga as 10⁹. A megabyte is then 1,000,000 bytes, a gigabyte is 1,000,000,000 bytes and 1 GB is exactly 1,000 MB. Page checked 19 Oct 2026. To convert, move the decimal point three places to the left.

Binary: 1 GiB is 1,024 MiB

NIST, prefixes for binary multiples lists the binary prefixes kibi (Ki), mebi (Mi), gibi (Gi) and tebi (Ti) as powers of two, and says they are not part of the SI. It gives 1 MiB as 1,048,576 bytes. Since 2³⁰ ÷ 2²⁰ = 1,024, 1 GiB is exactly 1,024 MiB. A gibibyte is 1.073741824 GB, or about 1.074 GB. Page checked 19 Oct 2026.

The two answers side by side

The same number gives different results depending on which rule the source used. The second column treats the number as MB, and the third treats it as MiB.

Why a drive shows less than its label

The NIST page on binary prefixes says that storage makers usually use megabyte to mean 1,000,000 bytes, while memory makers mean 2²⁰ bytes, and that the confusion is real. So a drive sold as 500 GB holds 500,000,000,000 bytes. A program that counts in 1,024 steps and still writes GB will show 465.66. No bytes are missing. The same bytes are being counted in bigger units. The tool cannot tell which way your computer counts, so check whether it writes GB or GiB.

Worked examples

• 700 MB. 700 ÷ 1,000 = 0.7 GB.
• 1,500 MB. 1.5 GB.
• 4,096 MB. 4.096 GB by the decimal rule. If it is 4,096 MiB, it is exactly 4 GiB.
• 25 MB. 0.025 GB. A small file gives a small GB number.
• 3 GB back to MB. 3 × 1,000 = 3,000 MB, or 3,072 MiB for 3 GiB.

GB back to MB

A GB is 1,000 MB and a GiB is 1,024 MiB, so the second and third columns grow at slightly different rates.

MB is not Mb

A capital B is a byte and a small b is a bit. NIST writes the bit as "bit", as in 1 Kibit, and the byte as B. There are 8 bits in a byte, so 1 MB is 8 Mbit. A speed in Mbps is megabits per second, which is a different thing from a size in MB. For speeds, use Kbps to Mbps.

Mistakes that are specific to MB and GB

The first is dividing by 1,024 when the source is decimal. A file listed as 1,000 MB is exactly 1 GB and not 0.9766 GB. The second is moving the decimal point the wrong way. A GB is bigger, so the number gets smaller. The third is trusting a label for a limit. A limit given in MB may be counted either way, because the unit has been used both ways, so keep some room. The fourth is the bit and byte mix-up above.

Who uses MB to GB

People checking a download against a data plan, a file against an upload limit or a recording against free space. Video makers who see a file in MB and a drive in GB. To shrink a file to fit, see Compress video for email. To plan a size from a bitrate, use the Video bitrate calculator.