The ratio or bits with errors to the total number of bits detected, usually expressed as a number with an exponent to a power of 10. Used to measure the quality of a signal path.

A measure of transmission quality, expressed as a ratio. The BER indicates how many bits are errored (incorrectly received) in a given bit stream. Generally notated as a negative exponent. For example, 1 x 10E -7 indicates one out of ten million bits (1 of 10, 000,000) are in error. Although a ratio, it is commonly referred to as “bit error rate."

The ratio of the number of bits received in error to the total number of bits transmitted in a given time interval.

The number of erroneous bits divided by the total number of bits transmitted, received or processed over some stipulated period. Note 1: Examples of bit error ratio are (a) transmission BER, i.e, the number of erroneous bits received divided by the total number of bits transmitted; and (b) information BER, i.e., the number of erroneous decoded (corrected) bits divided by the total number of decoded (corrected) bits. Note 2: The BER is usually expressed as a coefficient and power of 10; for example, 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 out of 105 or 2.5 x 10–5.

In telecommunication, an error ratio is the ratio of the number of bits, elements, characters, or blocks incorrectly received to the total number of bits, elements, characters, or blocks sent during a specified time interval. The error ratio is usually expressed in scientific notation; for example, 2.5 erroneous bits out of 100,000 bits transmitted would be 2.5 out of 105 or 2.5 × 10-5. Some software may display this as "2.5e-04".