Calculate voltage gain for inverting and non-inverting op-amp configurations
Electrical Calculator
Op-amp gain — Quick answer
Op-amp (operational amplifier) gain is set by feedback resistors. Inverting and non-inverting configurations have different formulas; both produce stable, predictable amplification independent of the op-amp's open-loop gain.
Non-inverting: Av = 1 + Rf/Rg Inverting: Av = − Rf/Rin Differential: Av = Rf/Rin (V+ − V−)
Rf — feedback resistor (Ω)
Rg — ground resistor (non-inverting input bias)
Rin — input resistor (inverting configuration)
Av — closed-loop voltage gain (V/V)
Worked example: Non-inverting amp with Rf = 10 kΩ, Rg = 1 kΩ. Gain = 1 + 10k/1k = 11 V/V (= 20.8 dB). Input 100 mV → output 1.1 V.
Common op-amp gain configurations
Rf
Rg / Rin
Non-inverting gain
Inverting gain
10 kΩ
10 kΩ
2 (6 dB)
−1 (0 dB)
10 kΩ
1 kΩ
11 (20.8 dB)
−10 (20 dB)
100 kΩ
1 kΩ
101 (40 dB)
−100 (40 dB)
1 MΩ
1 kΩ
1,001 (60 dB)
−1,000 (60 dB)
Standard / source: Texas Instruments / Analog Devices op-amp datasheets; classic Sedra/Smith microelectronics textbook.
Used for: Sensor signal conditioning, audio preamps, instrumentation amplifiers, active filters, voltage followers, ADC drivers.
📡 Op-Amp Gain Calculator
Formula
This calculator uses the standard op-amp gain calculator formula:
Non-Inverting Gain
Gain = 1 + (Rf / R1)
Frequently Asked Questions
What is op-amp gain?⌄
Op-amp gain is the ratio of output voltage to input voltage. For an ideal non-inverting amplifier: Gain = 1 + Rf/R1. For inverting: Gain = −Rf/R1.
What is the difference between inverting and non-inverting op-amp?⌄
An inverting amplifier flips the phase of the output signal. A non-inverting amplifier maintains the same phase. Both amplify the signal; the choice depends on phase requirements.
How do I set op-amp gain to 10?⌄
For non-inverting: 1 + Rf/R1 = 10, so Rf/R1 = 9. Use Rf = 90 kΩ and R1 = 10 kΩ. For inverting: −Rf/R1 = −10, so Rf = 100 kΩ and R1 = 10 kΩ.
What is dB gain in op-amps?⌄
Decibel gain = 20 × log₁₀(|Av|). A gain of 10 = 20 dB; gain of 100 = 40 dB; gain of 0.1 = −20 dB (attenuation).
What is the gain-bandwidth product?⌄
The gain-bandwidth product (GBW) is a fixed value for a given op-amp. As gain increases, bandwidth decreases proportionally. For example, GBW=1 MHz at gain=10 gives 100 kHz bandwidth.
What is a voltage follower (unity gain buffer)?⌄
A voltage follower is a non-inverting op-amp with Rf = 0 and R1 = infinity (or just the output connected to the inverting input), giving Gain = 1. It provides high input impedance and low output impedance.
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