Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Feedback resistor (Ω)

Required number input.

Input resistor (Ω)

Required number input.

Compute the op-amp difference amplifier gain as Rf / Rin. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Differential gain (ratio)

The resulting differential gain returned as a number.

• Amplifier gain and rejection calculations are small-signal approximations unless the operating point is checked. Gain-bandwidth, slew rate, input and output range, stability, noise, offset, bias current, loading, and frequency-dependent CMRR can limit the result.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Op-Amp Open-Loop Gain

  Calculate open-loop voltage gain A=Vout/(V+−V−) from an unsaturated operating-point measurement. Differential input cannot be zero; this scalar does not capture frequency-dependent gain.

• Instrumentation Amplifier Cmrr Calc

  Common-mode rejection ratio in decibels from measured differential and common-mode voltage gain magnitudes.

• Opamp Input Offset Current

  Calculate op-amp input offset current as the absolute difference between the two input bias currents, using signed current measurements.