Kilobit Per Second (kbps)

ComputingCurrent unit

1,000 bits per second. Used for voice calls and low-rate links.

1 kilobit per second = 1,000 bits per second (exactly).

1 kilobit per second = 1,000 bits per second

About the kilobit per second

Kilobit rates belong to the age of telephone wires. In 1962 AT&T introduced the Bell 103A, a full-duplex modem that sent 300 bit/s over ordinary phone lines, and by 1976 the Bell 212A had reached 1,200 bit/s. Speeds then climbed in steps through the 1990s, until the V.90 standard approved in 1998 offered 56 kbit/s downstream, with 33.6 kbit/s going the other way. That ceiling defined the dial-up era for many home users.

A kilobit per second is 1,000 bit/s, using the standard SI meaning of kilo, and it is still the natural unit for anything lightweight. A digital voice channel using PCM takes 64 kbit/s. MP3 files are often encoded at 128 kbit/s as a mid-range setting, with 320 kbit/s the highest the format supports. Divide by eight to get bytes: 8 kbit/s is 1 kB/s, so a 56 kbit/s modem moves about 7 kB/s, and fetching a 1 MB file over it would take roughly two and a half minutes.

Sources: Wikipedia: Modem (Bell 103, 212A, V.90 history); Wikipedia: Bit rate (voice and MP3 rates); Wikipedia: Kilobit

Kilobit Per Second conversion chart

1 kilobit per second expressed in every other data transfer rate unit:

Unit1 kilobit per second
Bps1,000
Mbps0.001
Gbps0.000001
MB/s0.000125
Tbps1×10⁻⁹
B/s125
KB/s0.125
GB/s1.25×10⁻⁷
MiB/s0.0001192092896
Kibit/s0.9765625
Mibit/s0.0009536743164
Gibit/s9.313225746×10⁻⁷
KiB/s0.1220703125
GiB/s1.164153218×10⁻⁷

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