What is the difference between MB and MiB storage sizes?

MB uses a decimal prefix, while MiB uses a binary prefix, so the two represent different capacities. 1 MB equals 1000000 bytes, whereas 1 MiB equals 1048576 bytes. Check the displayed unit when comparing files, disks, or system reports. A difference caused by prefix conventions is not automatically missing storage, although actual formatting and filesystem overhead can involve separate capacity considerations beyond this unit conversion.

How do bits, bytes, and Mbps convert into megabytes per second?

1 byte contains 8 bits, so under decimal prefixes 8 Mbps corresponds to a theoretical 1 MB per second. Real transfers also depend on protocol overhead and link conditions. This tool converts the numeric units but does not measure network performance or guarantee a file download rate. Check whether a source uses bits or bytes before comparing a connection specification with the throughput reported by an application.

Do KB and KiB use factors of 1000 or 1024?

This tool treats KB as 1000 bytes and KiB as 1024 bytes, listing the decimal and binary families separately. Larger prefixes continue using the corresponding factor within each family. Confirm how an external source defines its labels before converting a reported size. Capitalization alone is not a reliable substitute for that definition, especially when older software displays an ambiguous abbreviation for a value calculated using a different prefix convention.

Data size converter

Convert bytes, bits and both decimal and binary size prefixes

Computed in your browser

Pick the units at both ends to see the result. KB is 1000 bytes and KiB is 1024, so pick the one your figure actually uses.

Value

Unit of the value

Target unit

Common conversions

Significant digits

This affects display only. Conversion always uses full precision.

Every unit at once
Unit	Symbol	Result
Bit	bit
Byte	B
Kilobyte	KB
Megabyte	MB
Gigabyte	GB
Terabyte	TB
Petabyte	PB
Kibibyte	KiB
Mebibyte	MiB
Gibibyte	GiB
Tebibyte	TiB
Pebibyte	PiB
Kilobit	kbit
Megabit	Mbit
Gigabit	Gbit

Example

Input

1 GB

Example result

B     1000000000
MB    1000
GiB   0.931322574615
MiB   953.674316406

The same capacity expressed with decimal and binary prefixes differs by about 7 percent.

Technical details & limits

Conversions run through the byte, with eight bits to a byte. Decimal prefixes step by 1000 and binary prefixes by 1024; the two families are listed separately and never mixed. Bandwidth units such as the megabit follow the decimal prefixes.

About this tool

Enter a value and pick its unit to get bits, bytes and both prefix families at once: decimal KB, MB, GB, TB and PB stepping by 1000, binary KiB, MiB, GiB, TiB and PiB stepping by 1024, plus the kilobit, megabit and gigabit used for bandwidth. The two families are listed separately rather than mixed.

Use cases

Explain why a drive’s advertised capacity does not match what the system reports.
Convert bandwidth in megabits into megabytes per second.
Size up a log file or dataset in different units.

How to use

Type a number. Decimals and scientific notation such as 1.5e3 are accepted.
Pick the unit the value is in and the unit you want it in. The ⇄ button swaps the two.
The summary line gives the target unit; the table below lists the decimal and binary prefixes separately rather than mixing them.
Adjust the significant digits for a shorter or longer number. The conversion itself always runs at full precision.

Notes

This page follows the SI and IEC definitions: KB is 1000 bytes and KiB is 1024 bytes. Many operating systems still label 1024 bytes as “KB”, a historical conflation, so choose the unit that matches where your number came from. Bits and bytes convert at eight bits to the byte.

FAQ

What is the difference between MB and MiB storage sizes?: MB uses a decimal prefix, while MiB uses a binary prefix, so the two represent different capacities. 1 MB equals 1000000 bytes, whereas 1 MiB equals 1048576 bytes. Check the displayed unit when comparing files, disks, or system reports. A difference caused by prefix conventions is not automatically missing storage, although actual formatting and filesystem overhead can involve separate capacity considerations beyond this unit conversion.
How do bits, bytes, and Mbps convert into megabytes per second?: 1 byte contains 8 bits, so under decimal prefixes 8 Mbps corresponds to a theoretical 1 MB per second. Real transfers also depend on protocol overhead and link conditions. This tool converts the numeric units but does not measure network performance or guarantee a file download rate. Check whether a source uses bits or bytes before comparing a connection specification with the throughput reported by an application.
Do KB and KiB use factors of 1000 or 1024?: This tool treats KB as 1000 bytes and KiB as 1024 bytes, listing the decimal and binary families separately. Larger prefixes continue using the corresponding factor within each family. Confirm how an external source defines its labels before converting a reported size. Capitalization alone is not a reliable substitute for that definition, especially when older software displays an ambiguous abbreviation for a value calculated using a different prefix convention.

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