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Data Converter

Convert between bytes, bits, megabytes, and other digital data units.

About the Data Converter

The Data Converter turns a quantity of digital information written in one unit into the same quantity written in another — bytes to bits, megabits to megabytes, gigabytes to terabytes. It uses the decimal convention throughout: one kilobyte is 1,000 bytes, not 1,024. That is the convention drive makers, network speeds and the SI prefixes themselves use.

How to convert bytes to bits

A byte is 8 bits. That has been settled since the 1960s, and every unit on this page follows from it.

bits=bytes×8bytes=bits÷8\begin{aligned} \text{bits} &= \text{bytes} \times 8 \\ \text{bytes} &= \text{bits} \div 8 \end{aligned}

Worked example. A 250-byte packet header carries 250 × 8 = 2,000 bits. Going the other way, a 100 Mb/s link moves 100 ÷ 8 = 12.5 MB/s at best, before protocol overhead takes its share.

Bytes to bits conversion table

Bytes (B)Bits (b)
18
216
324
540
1080
20160
50400
100800
2502,000
5004,000
1,0008,000

How large each unit is, in bytes

  • 1 byte = 8 bits.
  • 1 kilobyte (kB) = 1,000 bytes.
  • 1 megabyte (MB) = 1,000,000 bytes = 1,000 kB.
  • 1 gigabyte (GB) = 1,000,000,000 bytes = 1,000 MB.
  • 1 terabyte (TB) = 1,000,000,000,000 bytes = 1,000 GB.
  • The bit units — kilobit, megabit, gigabit, terabit — are each one eighth of the byte unit with the same prefix.

Real-world values

  • A plain-text SMS of 160 characters is 160 bytes, or 1,280 bits.
  • A 4-minute song at 320 kb/s is about 9.6 MB.
  • An hour of 1080p streaming video uses roughly 3 GB.
  • A 1 TB drive holds 1,000,000,000,000 bytes, which Windows reports as 931 GB.
  • A 1 Gb/s fibre line moves at most 125 MB/s.
  • A single-layer Blu-ray disc holds 25 GB, which is 200 gigabits.

Decimal and binary prefixes

This is where most confusion starts. Storage makers, network engineers and SI all use powers of 1,000: kilo, mega, giga, tera. Windows uses powers of 1,024 but prints the decimal letters anyway, which is why a drive labelled 1 TB appears as 931 GB. The correct names for the 1,024-based units are kibibyte, mebibyte and gibibyte (KiB, MiB, GiB). This converter works in decimal units only, so its answers match the number printed on the box and the figure on your internet bill.

Bits or bytes? Read the case of the letter

Network speeds are quoted in bits per second and file sizes in bytes, which is the second common source of confusion. The convention is that a lower-case b means bits and an upper-case B means bytes, so Mb/s and MB/s differ by a factor of eight. A 100 Mb/s line therefore downloads a 100 MB file in about eight seconds, not one.

Units this converter supports

Ten: bit, byte, kilobit, kilobyte, megabit, megabyte, gigabit, gigabyte, terabit and terabyte. Any pair converts in either direction, and bit units cross to byte units at 8 bits per byte.

Frequently asked questions

Does this converter use 1000 or 1024 bytes per kilobyte?

1000. One kilobyte is 1,000 bytes, one megabyte is 1,000,000 bytes and one terabyte is 1,000,000,000,000 bytes. That is the decimal SI convention used by drive makers, network speeds and most operating systems outside Windows.

Why does my computer show less space than the label on the drive?

Windows divides by 1024 three times but still writes the result as GB. A 1 TB drive really holds 1,000,000,000,000 bytes, which is 931 of those 1024-based units. Nothing is missing; the two systems label different quantities with the same letters.

How do I convert megabits to megabytes?

Divide by 8, because one byte is 8 bits. A 100 Mb/s connection therefore moves at most 12.5 MB/s, and a 1 Gb/s connection at most 125 MB/s, before protocol overhead.

Which units does this converter support?

Ten: bit, byte, kilobit, kilobyte, megabit, megabyte, gigabit, gigabyte, terabit and terabyte. Bit units are converted against byte units at 8 bits per byte.

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