What is the difference between MB and MiB?

MB (megabyte) uses the decimal SI standard where 1 MB equals 1,000,000 bytes (10 to the power of 6). MiB (mebibyte) uses the binary IEC standard where 1 MiB equals 1,048,576 bytes (2 to the power of 20). Hard drive manufacturers use decimal MB, which is why a 1 TB drive shows up as about 931 GiB in Windows.

How many bytes are in 1 GB?

In the decimal SI system, 1 GB equals exactly 1,000,000,000 bytes. In the binary IEC system, 1 GiB (gibibyte) equals 1,073,741,824 bytes. Most operating systems historically used binary counts but labelled them as GB, which caused confusion with storage capacity.

How do I convert megabytes to megabits?

Multiply megabytes by 8 to get megabits, since there are 8 bits in every byte. A 1.5 MB file is 12 megabits. Internet speeds are measured in megabits per second (Mbps), so this conversion is important when calculating download times.

File Size Converter

File sizes are expressed in two different systems that use the same-sounding names but different numbers, and this causes persistent confusion when you compare what a hard drive manufacturer says versus what your operating system reports. The decimal SI system, used by drive makers and most consumer products, defines a kilobyte as 1,000 bytes, a megabyte as 1,000,000 bytes and a gigabyte as 1,000,000,000 bytes. The binary IEC system, technically more correct for computer memory and historically used by operating systems, defines a kibibyte (KiB) as 1,024 bytes, a mebibyte (MiB) as 1,048,576 bytes and a gibibyte (GiB) as 1,073,741,824 bytes. The gap between them grows at each step: 1 GiB is about 7 percent larger than 1 GB, which is why a 1 TB drive shows up as roughly 931 GiB in Windows. This converter takes a file size in any unit and displays all the common equivalents in both systems, including megabits (Mb) for bandwidth calculations since internet speeds are measured in megabits per second. Enter a value, choose the unit, and all conversions update instantly. The worked example below uses 1.5 GB as the default input.

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File size value

Unit

1,500 MB

decimal megabytes

Gigabytes (GB)1.5 GB

Megabits (Mb)12,000 Mb

Mebibytes (MiB)1,430.51 MiB

Gibibytes (GiB)1.40 GiB

Kilobytes (KB)1,500,000 KB

Bytes (B)1,500,000,000 B

Decimal: 1 KB = 1,000 bytes. Binary IEC: 1 KiB = 1,024 bytes. Megabits = Megabytes x 8.

How it works

The input value is converted to bytes first using the appropriate multiplier: decimal units use powers of 1,000 and binary IEC units use powers of 1,024. From the byte count, all other values are derived by dividing by the relevant multiplier. Megabits are bytes multiplied by 8 divided by 1,000,000. The same byte total is divided by 1,024 for KiB, 1,048,576 for MiB and 1,073,741,824 for GiB.

Worked example

Starting with 1.5 GB (decimal): 1.5 times 1,000,000,000 equals 1,500,000,000 bytes. In MB that is 1,500 MB. In megabits that is 12,000 Mb. In binary IEC, 1,500,000,000 divided by 1,048,576 equals approximately 1,430.51 MiB, and divided by 1,073,741,824 equals approximately 1.40 GiB. These match the defaults pre-filled above.

Related calculators

Download Time Calculator: how long a file will take at your connection speed.
Bandwidth Calculator: bandwidth needed for a given transfer volume and time.
Hexadecimal Calculator: arithmetic in base 16 with decimal and binary output.

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