How to Use Electric Power Calculator
The Electric Power Calculator covers three common scenarios — select the mode that matches your need:
- Power mode (P = V × I) — Enter the voltage (V) and current (A) of a device. The Electric Power Calculator returns power in both watts and kilowatts.
- Energy mode (E = P × t) — Enter the power (W) and usage duration (hours). The Electric Power Calculator returns energy consumed in Wh and kWh.
- Cost mode — Enter total energy in kWh and your electricity rate per kWh. The Electric Power Calculator returns the estimated electricity cost.
Switch between modes using the buttons at the top of the tool. Results update instantly as you type.
Formula & Theory — Electric Power Calculator
The Electric Power Calculator is built on three fundamental electrical formulas:
Power: P (W) = V (V) × I (A)
Energy: E (Wh) = P (W) × t (h)
Cost: Cost = E (kWh) × Rate ($/kWh)
| Symbol | Meaning | Unit |
|---|---|---|
| P | Electric power | W / kW |
| V | Voltage | Volts |
| I | Current | Amps |
| E | Energy consumed | Wh / kWh |
| t | Time of use | Hours |
| Rate | Electricity price | $/kWh |
The Electric Power Calculator applies unit conversions automatically: 1 kW = 1000 W and 1 kWh = 1000 Wh. When estimating monthly bills, multiply your daily kWh result by the number of days in the billing period and your utility's per-kWh rate.
Key Conversions
- 1 kW = 1,000 W
- 1 kWh = 1,000 Wh
- Monthly consumption (kWh) = Daily kWh × 30
Use Cases for Electric Power Calculator
The Electric Power Calculator is valuable across a wide range of everyday situations:
- Home appliances — Quickly find the power draw of your air conditioner, washing machine, or refrigerator using nameplate voltage and current ratings.
- Electricity bill estimation — Enter any device's kWh consumption and your rate to see the exact cost contribution, making the Electric Power Calculator a handy budgeting tool.
- Solar and off-grid planning — Calculate total load in kWh per day so you can properly size a battery bank or solar array.
- Electronics and DIY projects — Verify that a power supply or fuse is rated high enough by using the Electric Power Calculator to compute P from V and I before choosing components.
Whether you are reviewing your monthly utility bill or designing an electrical circuit, the Electric Power Calculator delivers fast, reliable results without any installation or sign-up.