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Voltage Calculator

Voltage is the force or electric potential difference that moves charge through a circuit. It represents the energy needed to move electrons from one point to another and is measured in volts (V). In a circuit, voltage is the potential difference that moves electrons from the source to another point.

Voltage drives current, using electrical energy to operate devices, light lamps, and perform various tasks. It is also essential for transmitting signals and stabilizing power in electrical systems, keeping circuits stable and ensuring devices work correctly.

In summary, voltage is the force or potential difference that moves charge through a circuit and is related to current and resistance. It is essential for operating electronic devices and stabilizing electrical systems.

Voltage

Voltage Calculation Method

Voltage is related to current and resistance as in Ohm's law, expressed as V = IR, where V is voltage (volts), I is current (amperes), and R is resistance (ohms). Voltage is therefore the product of current and resistance.

V = IR
The voltage (V) is 0 .

About This Calculator

Voltage (electric potential difference) is the "pressure" that pushes charge around a circuit, measured in volts (V). It is the difference in potential energy per unit charge between two points.

Enter current and resistance to find the voltage, or work and charge to calculate it from first principles.

Voltage is the potential difference that drives current, equal to current times resistance. In a series circuit the supply divides in proportion to resistance: 12 V across 2 Ω and 4 Ω gives 4 V and 8 V. In parallel every branch sees the full supply voltage, which is why household sockets are wired that way.

Key Formula:V = I × R · V = W / Q

Frequently Asked Questions

What is the difference between voltage and current?

Voltage is the potential difference that drives the flow; current is the actual rate of charge flow. An analogy: voltage is the water pressure and current is the litres per second moving through the pipe.

Why is mains electricity 120 V in the US and 230 V in Europe?

Historical and safety-driven design choices diverged early in the 20th century. Higher voltage transmits the same power at lower current, so 230 V systems use thinner copper — but the two grids interoperate through transformers and travel adapters.

Why does voltage divide in a series circuit?

The same current passes through every resistor, so V = IR makes each drop proportional to its resistance, and the drops must add up to the supply voltage — the statement of Kirchhoff voltage law.

Why do some countries use 110 V and others 220 V?

Both are compromises: higher voltage carries the same power with less current and thinner copper, lower voltage is safer to touch. Korea standardised on 220 V in the 1970s to cut transmission losses.

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Sources & last update

2026-10-19