Op-Amp Gain Calculator

Op-Amp Gain Formula

Worked Example

An inverting amplifier with Rᵢₙ = 10 kΩ, R_f = 100 kΩ and 0.2 V in:

1. G = −R_f ÷ Rᵢₙ = −100000 ÷ 10000 = -10
2. Vₒᵤₜ = G × V₁ = -2 V

Gain in dB 20 log|G|: 20 dB · Note: The output saturates near the supply rails; check that |Vₒᵤₜ| stays below them.

GATE tip

Closed-loop bandwidth = gain-bandwidth product ÷ noise gain. A 1 MHz op-amp at a non-inverting gain of 10 has about 100 kHz bandwidth; for an inverting gain of −10 the noise gain is 11.

More Analog and Digital Electronics Calculators

• ADC Resolution Calculator

  LSB = Vref / 2ⁿ, SNR = 6.02n + 1.76 dB

  code = floor(Vᵢₙ/LSB); ENOB = (SINAD − 1.76)/6.02

  Example: A 12-bit ADC with a 3.3 V reference converting 1.65 V: Resolution (1 LSB) = 0.805664 mV.

  Open the adc resolution calculator →

• Decibel Calculator

  dB = 10 log₁₀(P₂/P₁) = 20 log₁₀(V₂/V₁)

  dBm = 10 log₁₀(P / 1 mW)

  Example: A power ratio of 100: Gain = 20 dB.

  Open the decibel calculator →

• 555 Timer Calculator

  f = 1/(ln 2 (R₁ + 2R₂)C) ≈ 1.44/((R₁ + 2R₂)C)

  duty = (R₁ + R₂)/(R₁ + 2R₂); monostable T = ln 3 × RC ≈ 1.1RC

  Example: An astable 555 with R₁ = 1 kΩ, R₂ = 10 kΩ and C = 10 µF: Frequency f = 6.86998 Hz.

  Open the 555 timer calculator →

• LED Resistor Calculator

  R = (V_s − n V_f) / I_f

  n LEDs in series; resistor power P = (V_s − nV_f) I_f

  Example: One 2 V LED at 20 mA from a 5 V supply: Series resistor R = 150 Ω.

  Open the led resistor calculator →

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures .

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.