Inverting Op Amp Calculator
Design an inverting amplifier stage and check its input impedance and offset.
About Inverting Op Amp Calculator
The inverting input is held at a virtual earth by feedback, so the input impedance is simply the input resistor. Output swing is limited to roughly 1.5 V inside each rail for most op-amps. Low input resistors give low input impedance, which can load the source — the main drawback of the inverting configuration.
Formula
Inverting Op Amp
A = −R_f ÷ R_in; input impedance = R_in
- virtual earth
- The inverting input sits at ground potential, which fixes input impedance at R_in
Worked example
With the default values below, Inverting Op Amp Calculator returns Gain of -10.0000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Input resistorminimum 0.01 ohm
- 2,200 ohm
- Feedback resistorminimum 0.01 ohm
- 22,000 ohm
- Input voltageminimum -50 V
- 0.5 V
- Supply railminimum 0.1 V
- 15 V
Results
- Gain
- -10.0000
- Output Voltage
- -5.00000 V
- Input Impedance
- 2,200.00 ohm
- Maximum Input Before Clipping
- 1.35000 V
- Clipping Status
- Within the linear range
Step by step
- 1Values used
- 2Inverting Op Amp
- 3Gain= -10.0000
- 4Output Voltage= -5.00000 V
- 5Input Impedance= 2,200.00 ohm
- 6Maximum Input Before Clipping= 1.35000 V
- 7Clipping Status= Within the linear range
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax or compounding frequency into account.
- Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Inverting Op Amp calculated?
A = −R_f ÷ R_in; input impedance = R_in The inverting input is held at a virtual earth by feedback, so the input impedance is simply the input resistor. Output swing is limited to roughly 1.5 V inside each rail for most op-amps.
Why does Inverting Op Amp matter?
Low input resistors give low input impedance, which can load the source — the main drawback of the inverting configuration.
What values do I need to enter?
This calculator takes 4 inputs: Input resistor, Feedback resistor, Input voltage, Supply rail. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.