Hubs:
Top Tools:
Physics • Watt Calculator | Electrical Power

Watt Calculator | Electrical Power

Calculate electrical power in watts from voltage and current using Ohm's Law (P = V × I).

Current (I = V / R)
8.00 Amperes (A)
Power (P = V × I)
960.00 Watts (W)
Be the first person to rate this calculator
AdvertisementIn-Article
Calculation Guide & Reference

Electrical Power (Watts) Mathematics

Watt calculator computes electrical power in watts from voltage and current using Ohm's Law.

Standardized Mathematical Formula
P = V × I

Electrical power in watts equals voltage (in volts) multiplied by current (in amperes) — one of the three core relationships in Ohm's Law, alongside V = IR.

Variables:
V:Voltage, in volts
I:Current, in amperes
P:Power, in watts
How It Works (Step-by-Step)
  • 1Enter the voltage and resistance (or current) of the circuit.
  • 2View the current and power in watts.
Real-World Numerical Example
120V at 5 Amps

A household appliance draws 5 amps on a 120V circuit.

•P = 120 × 5 = 600 watts.
Result: The appliance draws 600 watts of power.
Calculation Best Practices & Tips
Maintain consistent SI units (meters, kilograms, seconds, amperes, volts) across all variables before computing.
Check vector sign conventions (e.g., downward acceleration due to gravity g = -9.80665 m/s²) in projectile motion problems.

Frequently Asked Questions (FAQ)

Rearrange the formula: I = P ÷ V — divide the power in watts by the voltage in volts to get current in amps.

For simple DC or purely resistive AC circuits they're the same; in AC circuits with reactive loads (motors, capacitors), volt-amps (apparent power) can exceed watts (real power) due to phase differences — a distinction called power factor.

Explore12 PhysicsCalculators

Kinematics velocity, Ohm's law electricity, thermodynamics, optics, fluid pressure, and projectile physics.

More in Physics

Top Similar Tools (Physics)

Tags:
Looking for More Calculators?

Explore more tools in Physics (5+ more calculators available)

Browse our complete directory with category filters, formulas, and verified engines.