GB to MB Converter
Convert gb to mb instantly, with every other common unit shown too. Free, and runs entirely in your browser — nothing you enter is uploaded or stored.
About Storage Units
Converts between decimal units (KB, MB, GB — powers of 1000) and binary units (KiB, MiB, GiB — powers of 1024). The distinction is the entire reason a “1 TB” drive shows as 931 GB in an operating system that reports binary sizes with decimal names.
Drive manufacturers, network equipment and most standards bodies use decimal. Windows, and a lot of tooling, reports binary quantities while labelling them GB. The numbers diverge by about 10% at gigabyte scale, and the gap grows with every step up.
Where it helps
- Both unit families in one conversion, with the difference made explicit.
- Covers bytes through petabytes and their binary counterparts.
- Explains the “missing” disk space without any arithmetic on your part.
- Accepts decimal input for fractional sizes.
Limits
- It cannot tell you which convention a given tool used — that depends on the tool.
- Bits and bytes are a separate axis; network speeds in Mbps belong in the Bandwidth Calculator.
- Real capacity also loses space to filesystem overhead, which no conversion accounts for.
- Loose usage of MB for MiB is widespread, so labels alone cannot be trusted.
Frequently asked questions
Why does my 1 TB drive show as 931 GB?
The manufacturer sold you 1,000,000,000,000 decimal bytes. The operating system divides by 1024 three times and still writes GB, giving 931.
What is the difference between MB and MiB?
MB is 1,000,000 bytes; MiB is 1,048,576. The gap is about 4.8% at this scale and widens with each larger unit.
Which should I use in my own software?
Pick one and label it honestly. Binary units with i names for memory, decimal for storage and transfer, is the least surprising convention.
Why is my file bigger on disk than its reported size?
Filesystems allocate whole blocks, so a small file still occupies a full block. Many small files waste proportionally more.
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