Thermal Noise Calculator
Any circuit element that is above absolute zero will produce thermal noise, also called Johnson noise. What this means is that a simple resistor can produce white noise in any amplifier circuit. The only way to reduce this noise, is to lower the circuit's temperature or minimize the resistance. This noise is independent of the resistor's material composition.
This calculator calculates the noise RMS Voltage for a circuit element for a given bandwidth, resistance and temperature.
Vn(RMS)= sqrt(4*KB*T*R*(F2-F1)) Volts