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IT unit converter

Three conversions common in administration and support: a size in every unit (telling the GB, a power of 1000, from the GiB, a power of 1024), the time needed to transfer data at a given rate, and an integer from one base to another (decimal, hexadecimal, binary, octal).

Examples: 500 (GB of a disk), 1.5 (TB), 4096 (MiB).

bit —
4,000,000,000,000
B SI (×1000)
500,000,000,000
kB SI (×1000)
500,000,000
MB SI (×1000)
500,000
GB SI (×1000)
500
TB SI (×1000)
0.5
PB SI (×1000)
0.0005
KiB IEC (×1024)
488,281,250
MiB IEC (×1024)
476,837.1582
GiB IEC (×1024)
465.6612873
TiB IEC (×1024)
0.4547473509
PiB IEC (×1024)
0.0004440892099

Disk makers advertise GB (×1000) while Windows displays GiB (×1024) under the name “GB”: a 500 GB disk shows up as about 465 GB.

What the tool does

  • SI and binary sizes

    A byte, a kilobyte (1,000 bytes) and a kibibyte (1,024 bytes) are not the same thing. The tool shows the value in twelve units, from the bit to the pebibyte, with the standard of each.

  • Rates and transfer time

    How long to copy 50 GB at 1 Gbit/s? Enter the amount, the rate and the useful throughput: the duration is shown in days, hours, minutes and seconds, and the rate is converted into every unit (Mbit/s, MB/s…).

  • Number bases

    Decimal, hexadecimal, binary and octal with unlimited precision (computed on integers of any size), 0x, 0b, 0o prefixes accepted and binary grouped by four bits.

  • Forgiving input

    A decimal comma or point, spaces and underscores inside numbers are accepted; invalid, negative or oversized values are rejected with a message.

How to use it

Pick the tab, enter the value and the unit: the result is immediate and each line can be copied. For a transfer time, keep a useful throughput of 90 to 95% to get close to a local network in practice: the estimate stays theoretical, as it ignores latency, small files and the load on the network, disk or processor. Sizes use floating-point numbers (15 significant digits), enough to cover several exabytes.

FAQ

What is the difference between GB and GiB?

The gigabyte (GB) is 1,000,000,000 bytes, the gibibyte (GiB) is 1,073,741,824 bytes (1024³). Windows displays GiB but calls them “GB”, hence disk capacities that seem lower than on the box.

Why a rate in Mbit/s but a file in MB?

Carriers and network cards advertise bits per second, files are measured in bytes (1 byte = 8 bits). A 100 Mbit/s link transfers at best 12.5 MB per second.

Are very large hexadecimal numbers exact?

Yes: base conversions use arbitrary-precision integers, up to 512 digits, with no 53-bit rounding as with ordinary JavaScript numbers.