Electricity Calculator

Enter known values. The calculator will compute Power (W), Energy (kWh) for a given run time, and estimated Cost using your electricity rate. Leave fields blank if unknown.

Voltage (V) V Current (I) A Resistance (R) Ω Power (P) W Run time hours Rate $/kWh

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Results

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Notes: Energy (kWh) = Power (W) × Time (h) ÷ 1000. Power (W) = V × I. If Power left blank, calculator will try to compute it from V & I or from V & R or from I & R using Ohm’s Law.

Electricity Calculator Online – Calculate Power, Energy & Cost Easily

Intro

Electricity powers almost everything in our daily lives—from the lights in our homes to the devices we use at work. But many people are unsure how to calculate their electricity usage or estimate monthly costs. That’s where an Electricity Calculator online comes in handy.

An Electricity Calculator helps you quickly find out how much power an appliance consumes, how much energy it uses over time, and the total cost of running it. Whether you’re a homeowner trying to reduce bills, a student learning physics, or a business calculating expenses, this tool saves time and provides accurate results.

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Formula / Working

The Electricity Calculator uses three main formulas:

1. Power (W):

P=V×IP = V \times IP=V×I

Where:

• PPP = Power in watts
• VVV = Voltage (volts)
• III = Current (amperes)

2. Energy Consumption (kWh):

E=P×T1000E = \frac{P \times T}{1000}E=1000P×T​

Where:

• EEE = Energy in kilowatt-hours
• PPP = Power in watts
• TTT = Time in hours

3. Electricity Cost ($):

Cost=E×R\text{Cost} = E \times RCost=E×R

Where:

• RRR = Electricity rate per kWh

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Step-by-Step Usage

Using the Electricity Calculator online is simple:

1. Enter the appliance’s power rating (in watts or kW).
2. Input the number of hours the appliance runs daily.
3. Provide the electricity rate (cost per kWh from your bill).
4. Click “Calculate.”
5. The tool will show:
   • Energy consumed (kWh)
   • Monthly or yearly consumption
   • Estimated electricity cost

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Examples

Example 1 – Laptop Usage

• Power: 100W
• Time: 5 hours/day
• Rate: $0.15/kWh

E=100×51000=0.5 kWh/dayE = \frac{100 \times 5}{1000} = 0.5 \text{ kWh/day}E=1000100×5​=0.5 kWh/day

Monthly = 15 kWh → Cost = 15 × 0.15 = $2.25/month

Example 2 – Air Conditioner

• Power: 1500W
• Time: 8 hours/day
• Rate: $0.20/kWh

E=1500×81000=12 kWh/dayE = \frac{1500 \times 8}{1000} = 12 \text{ kWh/day}E=10001500×8​=12 kWh/day

Monthly = 360 kWh → Cost = 360 × 0.20 = $72/month

Example 3 – Refrigerator

• Power: 200W
• Time: 24 hours/day
• Rate: $0.12/kWh

E=200×241000=4.8 kWh/dayE = \frac{200 \times 24}{1000} = 4.8 \text{ kWh/day}E=1000200×24​=4.8 kWh/day

Monthly = 144 kWh → Cost = 144 × 0.12 = $17.28/month

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FAQs

1. What is an Electricity Calculator?
It’s an online tool that helps you estimate energy usage and electricity costs for any appliance or device.

2. Do I need to know voltage and current?
Not always. If you already know the power rating (watts), you can calculate directly.

3. Can this tool help me reduce bills?
Yes! By calculating which appliances consume the most electricity, you can manage usage and save money.

4. Is the calculator accurate?
Yes, it provides close estimates, but actual usage may vary depending on appliance efficiency.

5. Does it work for both residential and business use?
Absolutely. You can use it for home, office, or industrial electricity calculations.