Non-Inverting Op-Amp Gain Calculator

This calculator works out the closed-loop voltage gain of a non-inverting operational amplifier circuit, a common building block in analogue electronics used for sensor buffering, preamps and instrumentation. You enter the feedback resistor Rf running from the op-amp output back to the inverting input, the ground resistor Rin from that same inverting input down to ground, and the input voltage Vin you want to feed in. From these it returns the voltage gain Av using the formula Av = 1 + Rf / Rin, the resulting output voltage (Av multiplied by Vin), and the feedback ratio Rf/Rin on its own, showing how much of the gain comes from the resistors versus the fixed plus-one term. Because the signal enters the non-inverting terminal, the output keeps the same polarity as the input, and the gain can never drop below one, unlike an inverting amplifier which can also attenuate. This configuration gives very high input impedance, the usual reason for choosing it to buffer sensors or high-impedance sources without loading them down. Use the calculator to size feedback resistors for a target gain, check an existing design, or see how output voltage shifts as you adjust either resistor. Results assume an ideal op-amp with infinite open-loop gain and bandwidth, so treat them as a close design estimate and check real-world limits like supply rails, bandwidth and slew rate for your chosen chip.

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