The communications channel capacity calculator uses the Shannon-Hartley theorem to calculate the bits per second that can be transmitted and received without error. The bandwidth of the communications channel in hertz should be entered along with the received signal power and the noise power in watts. Enter all values in either fractional integer or exponent notation (2.34, 1.2e-3, etc). Typically the received power level of the signal or noise is given in dBm or decibels referenced to one milliWatt. Since the power must be entered in watts, the value must be converted from dBm to watts. The noise power that should be entered is the larger of either the noise of the receiver or the thermal noise as calculated for the receiver impedance and temperature. Note that Gaussian noise is not additive so the largest noise source is used rather than a sum of all noise sources.