Tool · Analog electronics
Op-Amp Gain Calculator
Calculate closed-loop gain for inverting and non-inverting amplifiers, then see how resistor feedback sets the ideal output.
Calculate
Inputs
Calculate
Results
Real output is limited by the selected op-amp and its supply conditions.
Visualize
See the feedback path.
The schematic changes with the selected amplifier mode. V+ and V− are not physically shorted.
In the inverting configuration, Vin reaches V− through Rin and Rf feeds Vout back to V−. V+ is at ground/reference.
Understand
How the calculation works
Inverting gain
Av = −Rf / RinAv = −50 kΩ / 10 kΩ = −5 V/V
Vout = Av × VinVout = −5 × 0.2 V = −1 V
Why does the formula work?
The op-amp responds strongly to the voltage difference between V+ and V−. Under stable negative feedback and linear operation, its high open-loop gain makes only a very small differential input voltage necessary, so the ideal model treats V+ ≈ V−.
This is a feedback result, not a physical short between the inputs. Ideal op-amp input current is approximately zero.
With V+ at 0 V, negative feedback keeps V− close to 0 V, often called a virtual ground. V− is not physically connected to ground.
Apply
Ideal model vs. real op-amp
This calculator uses an ideal op-amp closed-loop model. It does not simulate device limits.
Supply rails limit the available output voltage and the input common-mode range.
Output swing may not reach the rails, especially under load.
Gain-bandwidth and slew rate limit closed-loop behavior at frequency and during large-signal changes.
Input offset, bias currents, and stability depend on the actual device and circuit conditions.
Always check the actual op-amp datasheet before treating an ideal output as achievable in a real circuit.