Op-Amp gain calculator

Bandwidth here is the small-signal -3 dB figure, GBW divided by the noise gain, and the noise gain is the stage's non-inverting gain, so an inverting stage of -10 still closes its loop at 11 times the unity frequency. Real stages droop earlier and lose output swing long before that: slew rate sets the full-power ceiling, and this tool does not know the supply rails, so it never claims a clipping verdict. Extreme resistors raise noise or load the source, and the 10 kΩ to 100 kΩ range avoids both. For the difference stage, resistor matching sets the common-mode rejection, not the op-amp.