Estimate electricity usage and cost based on the power requirements and usage of appliances.
Modify the values and click the calculate button to use
Estimated wattage ranges for common household appliances — actual usage may vary by model and age
Using our calculator is super straightforward. Here's exactly what to do:
Enter the wattage of your appliance. You'll find this on a sticker or in the manual. Most appliances list it clearly.
Enter how many hours per day you use it. Be honest here — if you leave your TV on for 6 hours, put 6.
Enter your electricity rate in cents per kWh. This is on your bill. In the US, it's usually between 10 and 30 cents.
Hit calculate and you'll see your daily, monthly, and yearly costs.
That's it. No PhD in electrical engineering required.
A 150-watt fridge running 24 hours/day at 14 cents/kWh: Daily: ~50¢ | Monthly: ~$15 | Yearly: ~$184. That's pretty reasonable. But an old 1990s fridge using 400+ watts? Over $40/month. Our calculator helps you spot these savings instantly.
This is the biggest confusion point I see on Reddit and Quora. People mix up watts and kilowatt-hours. They're not the same thing.
⚡ Watts
Measure power — how fast energy is used at any moment. Like your car's speedometer.
📊 Kilowatt-hours
Measure energy — total used over time. Like your car's odometer. This is what you're billed for.
So a 1000-watt microwave running for 1 hour = 1 kWh. A 100-watt bulb running for 10 hours = also 1 kWh. Same energy, different power levels and times. Our calculator converts automatically so you don't have to think about it.
Not all appliances are created equal. Here's what typically uses the most power:
But here's the thing — these are averages. Your actual usage depends on your specific appliances and habits.
Here's something most people don't know: your devices still use power when they're turned off. It's called standby power or vampire power.
Think about all the things with a little light on when "off": TVs, game consoles, phone chargers (even empty), microwaves with clocks, coffee makers, computers in sleep mode.
Each uses maybe 1-5 watts. But add them all up and you're looking at 50-100 watts running 24/7. That's about $5-10 per month for absolutely nothing. Our calculator can help — just add up standby wattage and run it for 24 hours.
Check the sticker or label — Most appliances have a metal or plastic plate with wattage. Look on the back, bottom, or side.
Check the manual — If you still have it, the manual usually lists power consumption.
Search online — Google "[appliance name] wattage" and you'll usually find it.
Use a Kill-A-Watt meter — Plugs into the wall, shows exact real-time usage. Costs about $20-30.
If you can't find exact wattage, use estimates: LED bulb = 8-12W, microwave = 800-1200W, hair dryer = 1200-1800W.
☀️ Summer
AC usage spikes. Your bill might double or triple.
❄️ Winter
Heating costs go up, especially with electric heat.
🌸 Spring/Fall
Usually the cheapest months — minimal heating or cooling needed.
When using our calculator, think about how many months per year each appliance actually runs. A space heater might only run 3 months, but a fridge runs 12.
Find the Biggest Hogs First
Look at your results and find appliances costing you the most. Replacing an old fridge or fixing a leaky AC saves way more than switching to LED bulbs.
Compare Old vs New Appliances
Calculate your old appliance's cost. Then look up a modern Energy Star model. The difference might pay for the new appliance in a year or two.
Change Your Habits
Turn off lights when leaving rooms. Unplug chargers. Run dishwasher only when full. Use a power strip for your entertainment center and turn it off at night.
Check Your Electricity Rate
Some utilities offer time-of-use rates — electricity is cheaper at night. Shifting usage (like running the dishwasher at 10 PM) can save 20-30%.
Consider Solar
If your costs are high and you have a sunny roof, solar might make sense. Use our calculator for total yearly usage, then compare to solar output.
Why does my bill not match the calculator?
Your bill includes fixed fees (connection charges). You might have missed some appliances. And actual usage varies from estimates. The calculator gives a good ballpark, not an exact bill.
Can I use this for my business?
Absolutely. Same principles apply. Just use your business electricity rate and equipment wattage. Commercial rates are sometimes different from residential.
What if my appliance doesn't list watts?
Look for amps and volts instead. Multiply them: watts = amps × volts. So 5 amps at 120 volts = 600 watts.
Before smart meters, someone had to physically come to your house and read the meter. That's why bills were monthly — they couldn't track daily usage. Today, smart meters send data every 15-30 minutes, letting you see real-time usage on your utility's website.
But even with smart meters, most people don't know how to interpret the data. That's exactly what our calculator helps with.
Here's a trick I learned from an energy auditor: walk through your house at night and feel every outlet and switch plate with the back of your hand. If any feel warm, that device is using power even when "off." Those are your vampire power sources.
Then use our calculator with the standby wattage of those devices. You might be shocked at what you find.
1 kW = 1,000 W. Kilowatt-hours (kWh) measure energy: 1 kWh = 1 kW for 1 hour.
1 BTU = 0.2931 watt-hours. 1 kWh ≈ 3,412 BTU. BTU/h is a unit of power.
1 mechanical hp = 745.7 watts. 1 metric hp = 735.5 watts.
1 ton ≈ 3,517 watts ≈ 12,000 BTU/h. Used for AC/refrigeration ratings.
Subtract previous reading from current reading to get kWh used. Multiply by your rate per kWh. Add any fixed fees from your bill. Our calculator can handle this for you.
A watt measures power (how fast energy is used). A kilowatt-hour measures energy (how much total was used over time). Think of watts as speed and kilowatt-hours as distance. Your bill charges for kilowatt-hours.
A typical 1500-watt space heater running 8 hours uses 12 kWh. At the US average rate of 14 cents/kWh, that's $1.68 per day or about $50 per month. Space heaters are surprisingly expensive.
It's almost always cheaper to turn it off. The idea that "it uses more energy to cool down again" is a myth. Less running time = less energy. Just don't turn it off for under 2 hours.
Look at your latest electric bill — it lists your rate in cents per kWh. US average is about 14 cents/kWh, ranging from 10 cents (Louisiana) to 30 cents (Hawaii). Call your utility if you can't find it.
Air conditioning is the main reason. A central AC can use 3000-5000 watts. Running it 8 hours/day in summer can add $100-200 to your monthly bill. Other factors include pool pumps and kids being home.
Vampire power is electricity used by devices when they're turned off but still plugged in — TVs, chargers, game consoles. Combined, it's typically 50-100 watts 24/7, costing $5-10/month for nothing.
Use a Kill-A-Watt meter ($20-30) — plug it into the wall, then plug your appliance into it. It shows real-time wattage. Or check the appliance label and multiply amps × volts if watts aren't listed.
Yes, for devices with standby power. Unplugging a TV, game console, and computer setup when not in use can save $5-15/month. Small savings per device, but they add up across the whole house.
Many utilities offer time-of-use rates where electricity is cheaper during off-peak hours (typically 9 PM to 7 AM and weekends). Check with your utility — shifting laundry and dishes to off-peak can save 20-30%.
A high-end gaming PC with a powerful GPU can use 400-600 watts while gaming. At 4 hours/day and 14 cents/kWh, that's about $8-10/month. Add a monitor and it's slightly more.
Almost always yes. A pre-2000 fridge might use 1000-1500 kWh/year ($140-210/year). A new Energy Star model uses 350-500 kWh/year ($49-70/year). The savings pay for the new fridge in 3-5 years.