GB to MB Storage Converter

By Suraj GiriUpdated 16 September 2026

In decimal storage units 1 GB is 1,000 MB, so multiply gigabytes by 1,000 to get megabytes. In binary units 1 GiB is 1,024 MiB.

This page converts storage from gigabytes to megabytes and leads with the decimal answer, because GB and MB carry SI prefixes, which stand strictly for powers of ten. The binary answer beside it is the count Windows File Explorer shows under the same MB label.

Going the other way? Convert MB back to GB →

How do I convert GB to MB?

GB to MB conversion multiplies by 1,000, because one gigabyte is 1,000 megabytes in the decimal prefixes; in binary units one gibibyte is 1,024 mebibytes, so the multiplier becomes 1,024.

1. Type the number of gigabytes into the box at the top of the page.
2. Multiply it by 1,000, the number of megabytes in one gigabyte.
3. Read the decimal answer in MB, the reading the symbols GB and MB carry in the SI.
4. If the figure was counted in steps of 1,024, read the binary answer beside it instead: the same number multiplied by 1,024, in MiB.

Gigabytes and megabytes are two rungs of one ladder; to move between any two storage units, including the binary units, use the full storage converter.

GB to MB Conversion Table

Each row gives the decimal answer and, beside it, the binary answer for the same figure read as GiB. Every value in it is exact.

Worked Example: 5 GB to MB

The first question for this page, worked both ways. Each reading passes through bytes, which is where the two part company.

A gigabyte is 1,000,000,000 bytes and a gibibyte is 1,073,741,824, so the same figure lands on two different byte counts before it is multiplied again.

Check it in reverse

Run each answer back through its own step and the starting figure returns: 5,000 MB / 1,000 = 5 GB, and 5,120 MiB / 1,024 = 5 GiB. To verify any other value, read the megabytes back as gigabytes and compare the result with the figure you started from.

Worked Examples: GB to MB

Each example gives the value first, then the working. Click a value to load it in the converter.

Every example above runs the other way too - turn each MB answer back into GB.

Where These Factors Come From

The factors and rules above are read from the knowledge base rather than typed for the page. These are the lines it holds for this pair.

• gigabyte (decimal), factor to byte 1000000000
• megabyte (decimal), factor to byte 1000000
• gibibyte, factor to byte 1073741824
• mebibyte, factor to byte 1048576
• SI Brochure (BIPM 9th edition) section 3, prefix rule The SI prefixes refer strictly to powers of 10. They should not be used to indicate powers of 2 (for example, one kilobit represents 1000 bits and not 1024 bits).
• binary prefixes, adoption The prefixes kibi (Ki), mebi (Mi), gibi (Gi) and tebi (Ti) stand for 2^10, 2^20, 2^30 and 2^40. The IEC first adopted them in 1999, as Amendment 2 to IEC 60027-2, and they are now part of IEC 80000-13.
• How this page reports a result result in the target unit, decimal (SI) reading first and binary (IEC) reading beside it where the prefixes differ; printed in full where it fits in 10 significant figures, otherwise rounded to 10

Which Reading Does Windows Use?

Windows File Explorer counts sizes in steps of 1024 and labels them KB, MB and GB rather than KiB, MiB and GiB.

So a size Windows lists in GB is counted in gibibytes. To match a figure copied from File Explorer, read the binary answer; to match a figure that follows the SI, read the decimal one.

Frequently Asked Questions

Related Conversions

• GB to KB multiplies by 1,000,000 - convert gigabytes to kilobytes.
• GB to TB divides by 1,000 - turn gigabytes into terabytes.
• KB to MB divides by 1,000 - turn kilobytes into megabytes.
• MB to KB multiplies by 1,000 - turn megabytes into kilobytes.
• KB to GB divides by 1,000,000 - convert kilobytes to gigabytes.
• TB to GB multiplies by 1,000 - break terabytes down into gigabytes.

The other storage units, including bits and the binary units, are on a single page for all the storage units.