Electricity Calculator – Estimate Energy Usage and Cost

Use this free electricity calculator to estimate electricity usage and cost for appliances based on power rating, usage time, capacity, and price per kWh.

Electricity Calculator

Enter appliance power, usage time, and electricity price to estimate daily, weekly, monthly, and yearly energy cost.

Electricity Calculator

Use the calculator below to estimate electricity usage and cost based on the power requirements and usage of appliances. The amount of time and power that each appliance is used varies significantly between households, so for the best results, adjust the usage to most accurately reflect your personal usage.

Typical appliance:

Appliance power:

Use/run at: % capacity

Usage:

Electricity Price: per kWh

Result

The following is the estimated average electricity usage for this appliance along with the cost of electricity over varying spans of time.

Electricity usage	Cost	Time span
36 kWh	$5.40	per day
252 kWh	$37.80	per week
1,095.8 kWh	$164.38	per month
13,149 kWh	$1,972.35	per year

This calculator assumes there are 30.44 days in a month and 365.25 days in a year on average.

Units of electricity

One of the most common units of electrical power for appliances is the watt (W). Other common units of power include kilowatts (kW), British thermal units (BTU), horsepower (hp), and tons.

Watts, kilowatts and kilowatt-hours

Watts (W) is a unit of power used to quantify the rate of energy transfer. It is defined as 1 joule per second.

A kilowatt is a multiple of a watt. One kilowatt (kW) is equal to 1,000 watts. Kilowatt-hours (kWh) are a unit of energy. One kilowatt-hour is equal to the energy used to maintain one kilowatt of power for one hour.

P = E/t and E = Pt

BTU and BTU/h

1 BTU = 0.2931 watt-hours
1 BTU = 0.0002931 kWh
1 kWh ≈ 3412 BTU

Horsepower

1 unit of mechanical horsepower = 745.7 watts
1 unit of metric horsepower = 735.5 watts

Ton

1 ton ≈ 3517 watts
1 ton ≈ 12000 BTU/h

Amount of energy used by common appliances

Common appliances	Estimated wattage (W)
Air Conditioner (HVAC)	2500-10000
Heater (portable)	750-2000
Refrigerator	500-1000
Microwave oven	750-1500
Electric vehicle charger	1,500-20,000
Desktop computer	100-250
Smart phone charger	5-25

Energy saving tips

Monitor your energy usage habits and turn off appliances not in use.
Replace older incandescent bulbs with efficient LED bulbs.
Use a programmable thermostat when possible.
Buy appliances with better energy efficiency ratings.
Improve insulation, windows, and shading to reduce heat loss or gain.

How to Use

Select a typical appliance or enter the power manually.
Choose the correct power unit.
Enter usage level, daily or periodic run time, and electricity price.
Click Calculate to see energy usage and cost estimates.

How This Calculator Works

This electricity calculator converts the appliance power into kilowatts, adjusts it by usage percentage, then calculates energy consumption in kilowatt-hours per day, week, month, and year. It also multiplies those usage values by your electricity price to estimate total cost.

Frequently Asked Questions

What does this electricity calculator measure?

It estimates appliance electricity usage in kWh and the cost over different time periods.

Can I use watts instead of kilowatts?

Yes. The calculator supports watts, kilowatts, BTU/h, horsepower, and tons.

Does this calculator show daily and yearly cost?

Yes. It shows usage and cost per day, week, month, and year.