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Non-Inverting Op-Amp Gain

A non-inverting op-amp produces an output that is in phase with the input, amplified by a factor of one plus the ratio of the feedback resistor to the input resistor. The gain is always at least one. This circuit has very high input impedance, which means it draws almost no current from the source. It is often used as a buffer or for amplifying weak signals without loading them down.

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Instrumentation Op-Amps

Non-Inverting Op-Amp Gain Calculator

Gain, resistor values, output voltage and error budget for a non-inverting amplifier.

Gain & dBVoltage followerE24 / E96 resistorsError budget
Vout = (1 + Rf / Rin) · Vin

Inputs

Results

Variables

Symbol Quantity Unit
V_out Output voltage V
R_f Feedback resistor Ω
R_in Input resistor Ω
V_in Input voltage V

What it means

The non‑inverting operational amplifier produces an output that is in phase with the input, with a gain given by V_out = (1 + R_f/R_in) · V_in. The gain is always greater than or equal to 1. The input impedance is very high (ideally infinite), making it suitable for buffering. This configuration is used in buffer amplifiers, voltage followers (when R_f=0), and as a building block for active filters. The gain is set by the ratio of feedback resistor to input resistor. Example: With R_f=9kΩ and R_in=1kΩ, the gain is 1 + 9 = 10. A 1V input gives V_out = 10V. This circuit is often used for impedance transformation without inversion.

Worked example

Non‑Inverting Op‑Amp – Practical Example

Real‑World
Scenario: A non‑inverting amplifier uses Rf = 100 kΩ and Rin = 10 kΩ. Find the gain and output for 1 V input.
ParameterValue
Rf100 kΩ
Rin10 kΩ
Vin1 V
FormulaVout = (1 + Rf/Rin)·Vin
1Gain = 1 + 100/10 = 11
2Vout = 11 × 1 = 11 V
Final Design Vout = 11 V ✓ Non‑inverting gain
Why: Non‑inverting gain is always ≥1, with no phase inversion – useful for buffering.

Common mistakes

Watch unit consistency and the assumptions behind the formula; misapplying it outside its valid conditions is the most frequent error.

Applications

Non‑inverting op‑amp gain V_out = (1 + R_f/R_in)·V_in amplifies the input without inversion. It offers high input impedance and is used in buffer and amplifier stages. Engineers use it to boost signals while maintaining phase, to provide high impedance inputs, and to drive loads. This configuration is widely used in sensor and audio applications.

  • Buffer and unity‑gain amplifier (voltage follower)
  • Signal amplification without inversion
  • High‑impedance input stage for sensors
  • Audio and RF amplifier stages
  • Educational understanding of non‑inverting amplifiers

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  • Published July 10, 2026
  • Last updated September 4, 2026