Electric Power Calculator
Calculate electric power calculator calculate electrical power P = V * I = I^2 * R = V^2 / R in Watts, kW, Horsepower (hp), and daily energy consumption kWh/day from voltage V, current I, or resistance R. Accurate physics formulas and unit conversions for engineers, students & technicians.
Calculate Electric Power & Energy Usage (P = V · I = I² R = V² / R)
Enter your physical parameters below to compute verified electric power metrics.
Calculation Results
Calculated using verified physical methodology: Electric Power Formula: P = V \cdot I = I^2 \cdot R = \V^2 / R
\text{Daily Continuous Energy: } E_{\text{daily}} = \frac{P_{\text{Watts}} \cdot 24\text{ hr}}{1,000} \text{ kWh}
Quick Summary
The Electric Power Calculator evaluates electrical rate of energy transfer ($P = V \cdot I = I^2 R = \V^2 / R$) in Watts (W), Kilowatts (kW), Electrical Horsepower (hp), and continuous energy consumption in kWh/day and kWh/month.
Formula Explanation
Electric Power Formula: P = V \cdot I = I^2 \cdot R = \V^2 / R
\text{Daily Continuous Energy: } E_{\text{daily}} = \frac{P_{\text{Watts}} \cdot 24\text{ hr}}{1,000} \text{ kWh}
How It Works
The Electric Power Calculator takes any two known electrical parameters ($V, I, R$) and computes electrical power ($P = V \cdot I$). It converts power into Kilowatts (kW), Megawatts (MW), Horsepower (hp), and calculates continuous energy usage ($E = P \cdot t$) per day and month.
Step-by-Step Worked Example
Practical Problem: An industrial electric oven operates at voltage $V = 230.0\text{ Volts}$ drawing a current $I = 10.0\text{ Amperes}$ across heating elements ($R = 23.0\ \Omega$). Calculate electric power $P$ and daily continuous energy consumption.
- Step 1: Identify Input Parameters: $V = 230.0\text{ V}$, $I = 10.0\text{ A}$, $R = 23.0\ \Omega$.
- Step 2: Apply the Electric Power Formula ($P = V \cdot I$): $P = 230.0\text{ V} \times 10.0\text{ A} = 2,300.00\text{ Watts (W)}$.
- Step 3: Convert Power to Kilowatts & Horsepower: $P = \2,300 / 1,000 = 2.300\text{ Kilowatts (kW)}$; Horsepower = $\2,300 / 745.7 = 3.084\text{ hp}$.
- Step 4: Calculate Daily Continuous Energy Consumption (24 hours): $E_{\text{daily}} = 2.300\text{ kW} \times 24\text{ hr} = 55.200\text{ Kilowatt-Hours (kWh/day)}$.
- Step 5: Calculate Monthly Energy (30 days): $E_{\text{monthly}} = 55.20 \times 30 = 1,656.00\text{ kWh/month}$. Total heat energy output = $2.3\text{ kJ per second}$.
Real-World Calculation Examples
Scenario 1: 230V / 10A Industrial Electric Oven
Parameters: $V = 230.0\text{ V}$, $I = 10.0\text{ A}$, $R = 23.0\ \Omega$
Result: $P = 2,300.00\text{ W}$ ($2.30\text{ kW}$, 3.08 hp, 55.2 kWh/day). Industrial oven power.
Scenario 2: 120V / 15A Kitchen Microwave Oven
Parameters: $V = 120.0\text{ V}$, $I = 15.0\text{ A}$
Result: $P = 1,800.00\text{ W}$ ($1.80\text{ kW}$, 2.41 hp). Microwave power rating.
Scenario 3: 240V / 30A EV Home Fast Charger
Parameters: $V = 240.0\text{ V}$, $I = 30.0\text{ A}$
Result: $P = 7,200.00\text{ W}$ ($7.20\text{ kW}$, 9.66 hp). Electric vehicle Level 2 charger.
Scenario 4: 12V / 0.5A LED Light Strip
Parameters: $V = 12.0\text{ V}$, $I = 0.5\text{ A}$
Result: $P = 6.00\text{ W}$ ($0.006\text{ kW}$, 0.144 kWh/day). Low-power LED strip.
Key Benefits of Using This Calculator
Utility Billing & Energy Usage Solver
Computes daily ($P_{\text{kW}} \times 24\text{ hr}$) and monthly kWh energy consumption for appliance electricity cost estimates.
Three Power Formula Variations
Calculates power from $V \cdot I$, $I^2 R$, or $V^2 / R$ seamlessly.
Multi-Unit Readouts
Outputs power in Watts, kW, Megawatts (MW), Horsepower (hp), and kWh/day.
100% Free & Client-Side
Executes locally in your browser with zero latency or web server transmission.
Frequently Asked Questions (FAQ)
What is electric power?
Electric power (P) is the rate at which electrical energy is transferred, converted, or dissipated by an electric circuit per unit of time (P = V * I in Watts).
What is the SI unit of electric power?
Watt (W), defined as 1 Joule per second (1 W = 1 J/s = 1 Volt * 1 Ampere).
What is the difference between power (W) and energy (kWh)?
Power (Watts) is the INSTANTANEOUS rate of energy flow; Energy (Kilowatt-Hours) is the CUMULATIVE total work done over time (Energy = Power * Time).
What is Real Power vs Apparent Power in AC circuits?
Real Power P (Watts) = V * I * cos(phi) performs actual physical work; Apparent Power S (VA) = V * I includes reactive power stored in inductors/capacitors.
How converts Watts to Kilowatts and Megawatts?
1 kW = 1,000 Watts; 1 MW = 1,000,000 Watts.
How converts Watts to Electrical Horsepower?
Divide Watts by 745.6999 (1 hp = 745.7 Watts).
Why does doubling current quadruple power dissipation (P = I² * R)?
Because current is squared in the power formula; doubling current through a fixed resistance quadruples heat generation (P_new = (2I)² * R = 4 * I²R).
Why do high-voltage power lines transmit electricity at hundreds of kilovolts (kV)?
By increasing transmission voltage V, current I is reduced for the same power (P = V * I); reducing current drastically decreases line loss power dissipation (P_loss = I² * R_wire).
How converts kWh to Joules?
Multiply kWh by 3,600,000 (1 kWh = 3.6 x 10^6 Joules = 3.6 MJ).
Who invented the unit Watt?
Named in 1882 in honor of Scottish engineer James Watt, inventor of the steam engine condenser.