• 🔊 Amp Gain Calculator

    Calculate amplifier voltage gain, gain in decibels, output voltage, and estimated output power from your input and output signal levels.

    Amplifier Results

    Voltage Gain —
    Gain —
    Estimated Output Power —
    Estimated Output Current —
    Voltage Gain:
    Gain = Vout ÷ Vin

    Gain in dB:
    dB = 20 × log₁₀(Vout ÷ Vin)

    Output Power:
    P = V² ÷ R
    What does amplifier gain mean?

    Amplifier gain describes how much an amplifier increases the voltage of an incoming signal. A voltage gain of 20 means the amplifier's output voltage is approximately 20 times its input voltage.

    Gain is commonly expressed in decibels because dB makes large ratios easier to compare. Amplifier gain is different from the position of a front-panel volume or gain knob.
    Important: The power calculation assumes a resistive load and RMS voltage. Real loudspeakers have impedance that changes with frequency, and actual amplifier output may also be limited by clipping, current capability, power supply voltage, and thermal protection.

  • An Amp Gain Calculator helps audio engineers, musicians, sound-system installers, speaker builders, and electronics hobbyists calculate how much an amplifier increases an incoming signal.

    Enter the amplifier's input voltage and output voltage to calculate its voltage gain and gain in decibels (dB). You can also select the connected speaker or load impedance to estimate output power and current.

    Voltage gain is the ratio between the amplifier's output voltage and input voltage. For example, if an amplifier receives a 1-volt RMS signal and produces 20 volts RMS at its output, its voltage gain is 20×. That same ratio is approximately 26 dB of voltage gain.

    Amplifier gain should not be confused with a volume knob. The gain specification describes the amplifier's electrical amplification ratio, while a level or gain control may simply reduce the signal entering a fixed-gain amplifier stage.

    The calculator can also estimate amplifier output power using the RMS output voltage and selected load impedance. Keep in mind that loudspeaker impedance is not perfectly constant. A speaker labeled 4 Ω or 8 Ω can vary considerably with frequency, so calculated wattage should be treated as an estimate rather than an exact measurement of real-world power.

    Tip: If you are setting amplifier gain for a speaker system, avoid using the gain control simply to make the system as loud as possible. Proper gain structure leaves enough headroom to reduce clipping, distortion, and unwanted noise.

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