Volts Calculator
Calculate volts from watts and amps using V = P / I, or from current and resistance using V = I × R.
Voltage— V
How to Calculate Volts
V = P / I
Voltage equals power (watts) divided by current (amps). Use this formula when you know the wattage and amperage of a device or circuit.
Alternative Formula (Ohm's Law)
V = I × R
Voltage also equals current (amps) multiplied by resistance (ohms). This is one of the fundamental forms of Ohm's Law.
Example:
A device drawing 5A with 24Ω resistance:
V = 5 × 24 = 120 volts
A device drawing 5A with 24Ω resistance:
V = 5 × 24 = 120 volts
FAQ
What is voltage?
Voltage (V) is the electrical potential difference between two points. It represents the "pressure" that pushes electric current through a conductor.
What are common voltages?
US residential: 120V (standard outlets), 240V (dryers, ovens). European: 230V. Industrial: 480V, 600V.
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Last updated: 2026-08-08