Enter your Voltage alongside either Power or Resistance, pick your Calculation Type, and this Volts to Amps Calculator works out your Current in both amps and milliamps — plus shows you the exact formula used to get there.
Current
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Current (Milliamps)
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Formula Used
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Volts (V) measure electrical potential difference or voltage in a circuit. It represents the force or pressure that pushes electrons through a conductor, similar to water pressure in a pipe.
Amps (A) or amperes measure electrical current, which is the flow of electrons through a conductor. It indicates how much electrical charge passes through a point in one second.
Ohm's Law states that current equals voltage divided by resistance (I = V / R). It's a fundamental principle in electronics that describes the relationship between voltage, current, and resistance.
To convert volts to amps using power, divide the power in watts by the voltage in volts: I(A) = P(W) / V(V). For example, 100 watts ÷ 12 volts = 8.33 amps.
To convert volts to amps using resistance, divide the voltage by the resistance: I(A) = V(V) / R(Ω). For example, 12 volts ÷ 4 ohms = 3 amps.
Ohms (Ω) measure electrical resistance, which opposes the flow of current through a material. Higher resistance means less current will flow for a given voltage.
You might need this calculation when sizing electrical components, determining circuit breaker requirements, calculating battery life, or checking if a device will work with your power supply.
This calculator works for DC circuits and resistive AC loads. For AC circuits with reactive components (motors, transformers), additional factors like power factor must be considered.