Data size converter
Convert any size into every decimal and binary unit, and see how long it takes to transfer.
Capital B = bytes, lowercase b = bits. 100 MB (megabytes) = 800 Mb (megabits) = 95.37 MiB (mebibytes). 100 Mb (megabits) = 12.5 MB.
Decimal (1000)
Binary (1024)
Bytes, bits and the 1000 versus 1024 trap
Data sizes are a constant source of small errors: a heap of "2 GB" that is really 2 GiB, a Kubernetes limit of 500M that is not 500Mi, a 100 megabit link that moves 12.5 megabytes per second, an upload that "should take a minute". Two prefix systems and two meanings of the letter b make mistakes easy and the arithmetic annoying.
Type a size in any unit (1.5 GiB, 500 MB, 100 Mb, 2048 bytes) and the converter shows it in every decimal unit (KB, MB, GB, TB, PB, EB) and every binary unit (KiB, MiB, GiB, TiB, PiB, EiB), in bytes and in bits, plus the best-fitting unit. Add a connection speed in megabits per second and it estimates the transfer time, which is the quickest sanity check for "how long will this backup, upload or image pull take".
Rules of thumb
- Memory, JVM heap sizes and most operating-system file sizes are binary (powers of 1024); disk marketing and network throughput are decimal (powers of 1000).
- Divide megabits by 8 to get megabytes. Real transfers are slower than the link rate because of protocol overhead, typically by 5 to 20 percent.
- In configuration files always state the unit explicitly and prefer the IEC forms (MiB, GiB) when you mean powers of 1024.
All numbers are calculated in your browser using standard floating-point arithmetic, which is exact for the sizes people normally work with.
Frequently asked questions
Why is my 1 TB drive only 931 GB?
Drive makers use decimal units (1 TB = 10^12 bytes) while operating systems often show binary units (1 TiB = 2^40 bytes, labelled GB by some systems). 10^12 bytes is about 931 GiB, so nothing is missing; the units differ.
What is the difference between MB and MiB?
MB (megabyte) is 1,000,000 bytes; MiB (mebibyte) is 1,048,576 bytes (1024 squared). The IEC introduced KiB, MiB and GiB to remove the ambiguity. Memory is normally binary, network speeds and storage marketing are decimal.
What is the difference between Mb and MB?
Lowercase b means bits and uppercase B means bytes. Network speeds are quoted in megabits per second (Mbps), file sizes in megabytes, and one byte is eight bits. A 100 Mbps link moves at most 12.5 MB per second.
Which units do Java and Kubernetes use?
The JVM options -Xmx512m and -Xmx2g are binary (MiB and GiB). Kubernetes distinguishes Mi and Gi (binary) from M and G (decimal), which is why 512Mi is 536.9 MB.