Op-Amp Gain Calculator
Inverting / non-inverting configuration — compute the voltage gain and dB from Rf and Rin.
What it does: Compute the voltage gain (V/V and dB) of an op-amp amplifier circuit.
When to use it: When designing an amplifier stage, choosing feedback resistors, or setting the gain.
MEANS Gain —; a minus sign means the output is inverted relative to the input.
No history yet. Each calculation is automatically saved to this device.
How to use the op-amp gain calculator
Pick a configuration and enter two resistors.
- 01
Pick the configuration
Inverting (output inverted relative to input) or non-inverting (in phase, gain ≥1).
- 02
Enter Rf and Rin
Feedback resistor Rf and input/ground resistor Rin, supports
10k,100k. - 03
Read the gain
Get the voltage gain (V/V) and decibels (dB).
Gain formulas
The two basic ideal op-amp configurations.
| Configuration | Gain formula | Characteristics |
|---|---|---|
| Inverting | Av = −Rf / Rin | Output inverted, can be <1 |
| Non-inverting | Av = 1 + Rf / Rin | In phase, always ≥1, high input impedance |
Ideal op-amp linear amplification.
Common questions, answered in 3 minutes
How do I choose between inverting and non-inverting?
Choose non-inverting when you need high input impedance and gain ≥1; choose inverting when you need inversion, a virtual ground, or to build a summer/integrator.
Why is the minimum non-inverting gain 1?
The non-inverting formula 1+Rf/Rin gives gain=1 when Rf=0 (a voltage follower). It cannot provide attenuation below 1.
Where does dB come from?
The voltage gain in decibels = 20·log₁₀|Av|. +6dB≈2×, +20dB=10×.
How much gain can I actually get?
It is limited by the op-amp gain-bandwidth product (GBW): the higher the gain, the narrower the bandwidth. For high gain at high frequency, check the GBW in the datasheet.
Standards and sources referenced by this tool
| Item | Value / Formula | Source |
|---|---|---|
| Op-amp gain | inverting −Rf/Rin / non-inverting 1+Rf/Rin | Ideal op-amp model |
Ideal op-amp model, no external API; in practice affected by GBW/offset.