Volts to Watts
Calculate power output from voltage. Choose whether you know the circuit resistance or current value.
Using resistance: P = V² ÷ R. Derived from Ohm's law where power equals squared voltage divided by resistance.
Interactive Electricity Flow Simulator
Watch the flow of electricity (electrons) change speed in real-time based on calculated wattage!
Visual scale relative to appliances
Ohm's Law relationship
The fundamental relationship governing voltage (potential), resistance (opposition), and power (work rate) in a closed circuit loop.
Understanding Volts and Watts
A volt (V) is the SI unit of electric potential difference or electromotive force. To convert volts to watts (W) (real power), you need a second electrical value: either current in Amperes (A) or circuit resistance in Ohms (Ω). This relationship is defined by Ohm's Law and Joule's Law.
Understanding potential differences (voltages) is key to configuring consumer electronics, computing power supply outputs, and working safely on standard commercial building systems.
If line voltage drops (due to long extension cables), the heat or light output of resistive loads drops by the square of the voltage reduction (P = V² / R).
How to Convert Volts to Watts
Use the appropriate formula depending on your known circuit variables:
- If current (Amps) is known:
P(W) = V(V) × I(A) - If resistance (Ohms) is known:
P(W) = V²(V) / R(Ω)
Global Voltage Standards
| Region | Standard Voltage | Common Application |
|---|---|---|
| North America | 120 V AC | Standard wall outlets |
| Europe & Asia | 230 V AC | Standard domestic power feeds |
| Car Electrical Systems | 12 V DC | Lead-acid batteries / accessories |
| USB Outlets (Standard) | 5 V DC | Mobile phone chargers |