Use this electricity cost calculator to estimate how much an appliance may cost to run. Enter the wattage, daily usage time, number of days, and your electricity rate per kWh to get a quick estimate of energy use and cost. This tool is helpful for checking monthly appliance costs, comparing devices, and planning ways to lower your electric bill.
Electricity Cost Calculator
Estimate appliance electricity cost by watts, hours used, days used, electricity rate per kWh, and number of appliances.
What This Calculator Helps You Estimate
This calculator is useful when you want to know how much electricity a home appliance may use over a day, week, month, or year. You can use it for air conditioners, space heaters, refrigerators, fans, TVs, washing machines, dryers, dehumidifiers, kitchen appliances, and other electric devices.
It can help you estimate:
- Total kWh used
- Daily electricity cost
- Monthly appliance cost
- Cost for multiple appliances
- Cost based on your local electricity rate
The result is an estimate, but it gives you a practical starting point before running an appliance for long hours.
What You Need Before Calculating
Before using the calculator, collect a few simple details.
| Detail | What It Means |
|---|---|
| Appliance wattage | How much power the appliance uses |
| Hours used per day | How long you run it each day |
| Number of days | Use 30 for a monthly estimate |
| Electricity rate | Your cost per kWh from your electric bill |
| Number of appliances | Use 1 unless calculating multiple devices |
You can usually find appliance wattage on the product label, user manual, box, or manufacturer’s website. Your electricity rate is usually shown on your utility bill as cents per kWh or dollars per kWh.
How to Calculate Electricity Cost
The basic formula is:
Electricity cost = Watts ÷ 1,000 × Hours used × Days used × Electricity rate
Here is the same formula in simple steps:
- Divide watts by 1,000 to convert watts to kilowatts.
- Multiply by the number of hours the appliance runs.
- Multiply by the number of days used.
- Multiply by your electricity rate per kWh.
For example, if a 1,500-watt space heater runs 4 hours per day for 30 days and your electricity rate is $0.16 per kWh:
1,500 ÷ 1,000 = 1.5 kW
1.5 × 4 × 30 = 180 kWh
180 × $0.16 = $28.80
So the estimated cost is $28.80 for 30 days.
What Is kWh?
kWh stands for kilowatt-hour. It is the unit your electric company uses to measure electricity usage.
One kilowatt equals 1,000 watts. If a 1,000-watt appliance runs for 1 hour, it uses 1 kWh.
A 500-watt appliance running for 2 hours also uses 1 kWh:
500 ÷ 1,000 × 2 = 1 kWh
This is why both wattage and run time matter. A high-watt appliance used for a short time may cost less than a low-watt appliance that runs all day.
How to Find Your Electricity Rate per kWh
Look at your electric bill for the cost per kWh. It may appear as:
$0.15 per kWh
or
15 cents per kWh
If your bill includes separate supply charges, delivery charges, taxes, and fees, your real average cost may be higher than the basic energy rate. For a rough average, divide your total bill by the total kWh used.
Example:
$180 bill ÷ 1,000 kWh = $0.18 per kWh
In that case, you would enter 0.18 into the calculator.
Appliance Cost Example
Let’s say you want to estimate the monthly cost of running a window air conditioner.
You enter:
| Input | Example |
|---|---|
| Appliance wattage | 900 watts |
| Hours per day | 8 hours |
| Days used | 30 days |
| Electricity rate | $0.17 per kWh |
| Number of appliances | 1 |
Calculation:
900 ÷ 1,000 = 0.9 kW
0.9 × 8 × 30 = 216 kWh
216 × $0.17 = $36.72
Estimated monthly cost: $36.72
This does not mean your full electric bill will rise by exactly that amount, but it gives you a useful estimate for that one appliance.
Common Appliance Electricity Cost Factors
Different appliances use electricity in different ways. Some run at full power only part of the time, while others use steady power as long as they are on.
| Appliance | Cost Factor to Watch |
|---|---|
| Air conditioner | Size, temperature setting, weather, run time |
| Space heater | High wattage and long run time |
| Refrigerator | Runs daily but cycles on and off |
| Clothes dryer | High energy use during each load |
| Dehumidifier | Can add up if used many hours daily |
| Ceiling fan | Usually low cost compared with AC |
| TV or monitor | Screen size and daily use time |
| Microwave | High wattage but short use time |
| Dishwasher | Cycle type and heated dry setting |
| Washing machine | Cycle type and water temperature |
Heating and cooling appliances usually have the biggest impact because they use more power and often run for longer periods.
Daily, Monthly, and Yearly Estimates
You can use the number of days field to estimate different time periods.
| Estimate Type | Days to Enter |
|---|---|
| Daily cost | 1 |
| Weekly cost | 7 |
| Monthly cost | 30 |
| Yearly cost | 365 |
For a quick monthly estimate, use 30 days. For a yearly estimate, use 365 days. For a temporary appliance, enter the exact number of days you plan to use it.
Why the Real Cost May Be Different
The calculator gives a helpful estimate, but actual usage can vary.
A refrigerator may not run at full power all day. An air conditioner may work harder during very hot weather. A space heater may cycle on and off depending on the room temperature. Appliances can also use more or less power depending on age, settings, efficiency, and condition.
Your utility bill may also include delivery charges, service fees, taxes, and other costs that are not part of the simple appliance calculation.
Use the result as a planning number, not a guaranteed bill amount.
Simple Ways to Lower Appliance Electricity Cost
The easiest way to lower electricity cost is to reduce run time or use appliances more efficiently.
Try these simple steps:
- Use timers or smart plugs for plug-in devices
- Clean filters on AC units, dryers, and dehumidifiers
- Avoid running space heaters longer than needed
- Use energy-saving modes when available
- Turn off devices that are not being used
- Compare wattage before buying a new appliance
- Raise the thermostat slightly in summer
- Lower the thermostat slightly in winter
- Use fans to support cooling instead of relying only on AC
- Run full loads in dishwashers and washing machines
Small changes matter most with appliances that run for many hours each day.
Accuracy Note
This electricity cost calculator is for general planning only. Actual electricity use may vary based on appliance efficiency, settings, duty cycle, weather, household habits, and local utility rates.
For the best estimate, use the wattage from your appliance label and the electricity rate from your current utility bill.
FAQs About Electricity Cost
How do I calculate electricity cost from watts?
Divide watts by 1,000 to convert them to kilowatts. Then multiply by hours used, days used, and your electricity rate per kWh.
What does kWh mean?
kWh means kilowatt-hour. It measures how much electricity you use over time. Your electric company uses kWh to calculate your energy usage.
How do I calculate cost per kWh?
To estimate your average cost per kWh, divide your total electric bill by the total kWh used. For example, a $160 bill with 1,000 kWh used equals $0.16 per kWh.
Is a higher-watt appliance always more expensive?
Not always. Cost depends on both wattage and run time. A high-watt appliance used for a few minutes may cost less than a low-watt appliance running all day.
Can this calculator estimate monthly electricity cost?
Yes. Enter 30 days to estimate monthly cost. You can also enter 7 days for weekly cost or 365 days for yearly cost.
Why is my real electric bill higher than the calculator result?
Your electric bill includes all appliances, lighting, heating, cooling, delivery fees, service charges, and taxes. This calculator estimates the cost for one appliance or a group of similar appliances.
What appliances cost the most to run?
Appliances that heat, cool, or run for long hours usually cost the most. Examples include air conditioners, space heaters, dryers, water heaters, and dehumidifiers.