Op-Amp Calculator
Solve for inverting and non-inverting op-amp Gain. Enter circuit values to calculate the selected electrical quantity.
Op-Amp Resistors
Electronics guide · Circuit components and networks
About Op-Amp Gain Calculator
Estimate ideal inverting and non-inverting voltage gain from a feedback resistor and input resistor. If an input voltage is entered, the page also estimates output voltages for both configurations.
Component calculations simplify a circuit into a formula or ideal model. Real parts have tolerances, ratings, parasitic effects, and wiring details that can change how a circuit behaves, so use the result as a design estimate and compare it with the component datasheet and circuit conditions.
How to Use This Tool
- 1.Enter feedback resistance Rf and input resistance Rin in the same unit.
- 2.Optionally enter an input voltage if you want estimated output values.
- 3.Calculate and compare the inverting and non-inverting gains. Check the op-amp supply rails and circuit configuration before applying the result.
Technical Details to Check
1.Match values to the right circuit position
Resistors, capacitors, inductors, and semiconductor pins are not interchangeable inputs. Follow the labels or diagram and check that each value belongs to the correct component or branch.
2.Ideal formulas have assumptions
A calculator may assume a balanced bridge, an ideal switch, a simple RC or RL network, or a specific transistor operating mode. Confirm that the real circuit matches that model before using the result.
3.Datasheet ratings still matter
Calculated values do not establish a safe operating point. Check voltage, current, power, temperature, frequency, and tolerance ratings for every part that will be used.
4.Small errors can move the result
Component tolerances and measurement uncertainty can change timing, bias, resonance, or dissipation. For a design with tight limits, calculate a range using realistic minimum and maximum values.
How the Calculation Works
For an ideal inverting amplifier, gain Av = −Rf/Rin. For a non-inverting amplifier, Av = 1 + Rf/Rin. Estimated output is gain multiplied by input voltage. Real output cannot exceed the op-amp's supply and depends on bandwidth, slew rate, input range, load, and topology.
Worked Example
With Rf=10 kΩ and Rin=1 kΩ, the ideal gains are −10 for the inverting circuit and 11 for the non-inverting circuit.
Where This Tool Can Help
Check resistor-ratio gain in basic op-amp designs or compare two common amplifier configurations.
Checking a first design estimate
Use the formula result to choose a likely component range, then test the circuit with real part values and operating conditions.
Learning how a circuit behaves
Change one input at a time and observe the result to see how a resistor, capacitor, inductor, or device parameter affects the calculation.
Comparing candidate components
Compare values on the same unit basis, then check package, tolerance, power rating, voltage rating, and availability in the relevant datasheet.
Reviewing a schematic
Use the result as a cross-check for a hand calculation, simulation, or design note while keeping the assumed topology clear.
Tips for More Reliable Results
- Use consistent units and copy component values carefully, including prefixes such as m, µ, n, and k.
- Check polarity, pin names, and series or parallel placement against the circuit diagram.
- Use worst-case component tolerances when a timing or operating range must stay within limits.
- Verify the result against datasheets and an appropriate bench measurement before building a safety-critical circuit.
Limitations and Assumptions
This ideal calculation does not model saturation, input offset, bias current, frequency response, stability, loading, or resistor tolerance. A theoretical output can exceed the supply rails. Check the datasheet and simulate or test the actual circuit.
The calculator can only model the values, topology, and operating assumptions represented by its inputs. It does not inspect a physical circuit, validate wiring, or confirm a part is safe for its electrical and thermal conditions. Use design documentation and datasheets for final component choices.
Frequently Asked Questions
Why is inverting gain negative?
The negative sign indicates a 180-degree phase inversion in the ideal model.
Does gain determine the output voltage?
Only with an input value and while the real amplifier remains within its operating limits.
Can this choose an op-amp?
No. Device selection needs bandwidth, supply, noise, output-drive, and other specifications.
Will the result exactly match a real circuit?
Not always. The formula may use ideal components and may not include tolerances, parasitic effects, loading, or temperature changes.
Can I select a component from the calculated value alone?
No. Also check ratings, tolerance, package, polarity, availability, and the circuit's operating conditions.