What this calculator does
Megabits and megabytes are both units of digital data, but they differ by a factor of 8, since one byte is 8 bits. A file listed as 800 Mb is the same amount of data as 100 MB, and mixing the two up is a common source of confusion, particularly because internet providers advertise connection speed in megabits per second while file sizes and storage are almost always shown in megabytes.
This calculator converts a plain data amount, such as a file or download size, between megabits and megabytes. It is deliberately separate from a speed conversion: converting megabits to megabytes here answers "how big is this file", not "how fast is this connection", which is a related but different question with its own dedicated conversion.
The formula
Divide a value in megabits by 8 to get megabytes, or multiply a value in megabytes by 8 to get megabits. The factor of 8 comes directly from the definition of a byte as 8 bits; no other conversion or rounding convention is involved.
| Term | Meaning |
|---|---|
| Mb | Megabits, a unit of data amount equal to 1,000,000 bits. |
| MB | Megabytes, a unit of data amount equal to 1,000,000 bytes, or 8,000,000 bits. |
The inputs explained
| Field | What to enter |
|---|---|
| Convert | Choose the conversion direction: megabits to megabytes, or megabytes to megabits. |
| Value | The data amount to convert, in whichever unit matches the direction chosen above. |
When to use it
Working out how big a download actually is
A download page or software changelog sometimes lists file size in megabits rather than the more familiar megabytes, and converting it clears up how much storage space or download data allowance it will actually use.
Checking a claimed file size against a download time
Once a file size is confirmed in megabytes, it can be compared against a connection speed in megabytes per second to sanity-check how long the download should take.
Understanding storage versus bandwidth figures
Storage devices and file sizes are specified in bytes (megabytes, gigabytes); network speeds are specified in bits per second (megabits per second). Keeping the two straight avoids under- or over-estimating either one.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Megabits converted to megabytes across common file sizes
A range of data amounts given in megabits, converted to megabytes.
| Megabits (Mb) | Megabytes (MB) | Equivalent in gigabytes |
|---|---|---|
| 100 Mb | 12.500 MB | 0.0125 GB |
| 500 Mb | 62.500 MB | 0.0625 GB |
| 800 Mb | 100.000 MB | 0.1000 GB |
| 1,000 Mb | 125.000 MB | 0.1250 GB |
| 2,000 Mb | 250.000 MB | 0.2500 GB |
| 5,000 Mb | 625.000 MB | 0.6250 GB |
Questions
Is this the same as converting Mbps to MB/s?
The underlying factor of 8 is the same, but the two questions are different. Mbps to MB/s converts a transfer speed (data per second); this calculator converts a plain data amount, such as a file size, with no time period involved at all.
Why do internet providers advertise speed in megabits but file sizes are shown in megabytes?
It is largely a convention split between industries: networking and telecommunications have historically measured throughput in bits per second, while computing and storage have measured amounts in bytes. Both units remain in everyday use, which is why converting between them comes up so often.
Does this use 1,000 or 1,024 as the conversion base?
This calculator uses the decimal (SI) definition, where 1 megabit is 1,000,000 bits and 1 megabyte is 1,000,000 bytes, which is the convention used by internet providers and most file-size listings. Operating systems sometimes use the binary base-1,024 convention instead (mebibytes), which gives slightly different figures.
How many megabits are in a gigabyte?
One gigabyte is 1,000 megabytes, and each megabyte is 8 megabits, so one gigabyte is 8,000 megabits. Switch the conversion direction above and multiply by 1,000 to check a gigabyte-sized figure directly.
For converting a network transfer speed rather than a fixed data amount, see the Mbps to MB/s calculator.