Op-Amp Calculator
Calculate gain and output voltage for common operational amplifier circuits. The live circuit graphic updates with the input values and the result directly on the diagram.
๐ง Practical note: These are ideal op-amp formulas. Real output may be limited by supply rails, input common-mode range, bandwidth and the actual op-amp datasheet.
Input Voltage
Feedback Resistor Rf
Ground Resistor Rg
Positive Rail
Negative Rail
Result
Presets:Gain 10Single supplyGain 10 exact
๐ Live non-inverting amplifier graphic
Input Voltage
Input Resistor Rin
Feedback Resistor Rf
Positive Rail
Negative Rail
Result
Presets:Gain -4.7Single supplyGain -10
๐ Live inverting amplifier graphic
Input Voltage
Positive Rail
Negative Rail
Presets:2V bufferNear railDual supply
๐ Live voltage follower graphic
V1 (โ input side)
V2 (+ input side)
Gain Set (R2 / R1)
Positive Rail
Negative Rail
Assumption
Presets:Gain 10 diffSmall differenceV2 - V1
โ๏ธ Live differential amplifier graphic
๐ Formula Reference
Non-Inverting
Gain = 1 + Rf / Rg
Vout = Vin ร Gain
Vout = Vin ร Gain
Inverting
Gain = -Rf / Rin
Vout = Vin ร Gain
Vout = Vin ร Gain
Voltage Follower
Gain = 1
Vout = Vin
Vout = Vin
Differential
If resistor pairs are matched:
Vout = (R2 / R1) ร (V2 - V1)
Vout = (R2 / R1) ร (V2 - V1)
๐ Quick Reference
๐ต Common Uses
Non-invertingsignal gain
Invertinggain + inversion
Bufferimpedance isolation
Differentialdifference sensing
๐ข Practical Limits
Rail clippingvery common
Input rangedatasheet check
Bandwidthgain dependent
Output currentlimited
๐ Good Design Habits
Matched resistorsbetter accuracy
Decouplingnear IC pins
Dual supplyfor bipolar signals
Rail-to-rail partfor low supply
๐ Engineering Notes
Ideal formulas are only the first stepThis calculator uses ideal op-amp equations. Real devices have finite bandwidth, offset voltage, slew rate and output swing limits.
Resistor ratio matters more than resistor sizeFor gain, the ratio between feedback and input/ground resistors is the key factor. Use practical values that do not load the source too much.
Watch for clipping on single-supply circuitsIf the ideal output goes below 0 V or above the positive rail in a single-supply circuit, the real op-amp output will clip.
Differential amplifiers need matched resistorsThe simple differential formula assumes the resistor pairs are accurately matched. Poor matching reduces common-mode rejection.
What does this Op-Amp Calculator do?
This op-amp calculator helps estimate the gain and output voltage for the most common operational amplifier circuits: non-inverting amplifier, inverting amplifier, voltage follower and differential amplifier. It is useful for students, hobbyists and practical electronics design work.
Why show the result on the circuit graphic?
Many users understand op-amp circuits faster when the input values, gain and final output appear directly on the circuit itself. This tool updates the graphic live so the math and the circuit stay connected visually.
Useful next-step tools
After checking op-amp gain, you may also want the Ohmโs Law Calculator, Voltage Divider Calculator, LED Resistor Calculator and Power Dissipation Calculator for resistor sizing and signal interface work.
โ Frequently Asked Questions
The ideal non-inverting gain is 1 + Rf/Rg, so output voltage is Vin multiplied by that gain.
The ideal inverting gain is -Rf/Rin. The negative sign means the output is inverted by 180 degrees relative to the input.
Real op-amps can clip near the rails, have limited input range, finite gain-bandwidth, offset voltage and output current limits. Always confirm the datasheet.