Household energy savings, made simple

Find out what any appliance costs to run.

Enter wattage, daily usage, and your electricity rate to see cost per hour, day, and month instantly. No accounts. No spreadsheets. Just a clear answer.

Tip: your calculator state updates live and can be shared with a copyable link.

Try the calculator See common use cases

Use your actual utility rate
Compare two appliances side by side
Built for renters, homeowners, and shoppers

Typical question

“What does my space heater cost per month?”

Hourly $0.21

Daily $1.68

Monthly $50.40

Based on 1500 W, 8 hours/day, and $0.14 per kWh.

Core tool

Electricity Cost Calculator

Start with one device, then switch on comparison mode to see which option is cheaper to run.

Quick appliance presets

Appliance name

Wattage (W)

Hours used per day

Days used per month

Electricity rate ($ per kWh)

Check your utility bill for a supply rate, or use a blended average rate.

Compare against a second appliance

Results

Ready to estimate your appliance cost

Enter your numbers to see hourly, daily, and monthly electricity cost.

Energy per hour —

Cost per hour —

Cost per day —

Cost per month —

How the math works

Cost per hour = (watts ÷ 1000) × electricity rate. Daily and monthly costs use your usage schedule.

Popular checks

Common appliance comparisons people care about

Portable AC vs. window AC
Space heater vs. heat pump
Old refrigerator vs. Energy Star model
Fan vs. central air for overnight cooling

WattWise starts with a simple calculator and expands into comparison guides that make savings decisions easier.

Why use WattWise

Faster than digging through bills or guessing online

Most people know the label wattage but not the real monthly cost. WattWise turns that into a practical answer you can use for budgeting, shopping, and cutting waste.

We keep the experience lightweight, readable, and useful on mobile so the answer is immediate when you need it.

FAQ

Quick answers for everyday energy questions

What electricity rate should I use?

Use the $/kWh figure from your electric bill if you have it. If your bill splits supply and delivery, a blended average often gives the most realistic estimate.

How accurate is the result?

The result is an estimate based on wattage and your stated usage. Real costs vary with utility pricing, duty cycles, and how often the appliance actually runs.

Can I compare two appliances?

Yes. Turn on comparison mode and add a second appliance to see which option is cheaper per month and how much you could save.