How to convert GB to MB
MB = GB × 1,000. The scale factor is the source-unit factor divided by the destination-unit factor.
Worked example
A 2.5 GB download converts to 2,500 MB.
- Start with 2.5 GB.
- Multiply 2.5 by 1,000.
- Report 2,500 MB, rounded to the precision of your original measurement.
Decimal GB to MB uses a factor of 1000. This calculation says nothing about download duration without a transfer rate.
Check the reverse conversion
1 MB = 0.001 GB. Use the megabyte to gigabyte converter to calculate in the opposite direction. This has its own formula and reference table.
Definitions that matter
A byte is eight bits. MB is not MiB, and GB is not GiB. Storage capacities are quantities; data-transfer rates such as Mbps add a time dimension and are not included here.
The base unit for this category is B. One GB corresponds to 1,000,000,000 byte; one MB corresponds to 1,000,000 byte. These definitions explain the relationship rather than relying on a rounded display value.
Sources and precision
Definitions: NIST binary prefixes. Calculations use double precision; the tool defaults to a readable rounded result, while tables show up to ten significant digits. Displaying more digits does not increase the accuracy of the original measurement.
Read our calculation methodology and content standards, or continue with decimal versus binary storage prefixes.