Electricity Cost Calculator
Calculate the electricity cost of any appliance or device. Find out daily, monthly, and yearly energy costs based on wattage and usage.
About this calculator
Monthly Cost is a straightforward chain multiplication: Power Consumption in watts converts to kilowatts, multiplies by Hours Used per Day and Days per Month to get total kilowatt-hours, then multiplies by Electricity Rate to get a dollar figure. All four inputs enter that chain the same way — as direct multipliers with no caps, thresholds, or diminishing effects — so a 10% change in any single input produces a 10% change in every cost output, and Power Consumption is the one most people adjust across the widest range (1 to 10,000 watts) in practice. Days per Month is read as a usage pattern rather than a calendar length: a device run 10 days a month is treated as run 120 days a year, so the yearly figures are always exactly twelve times the monthly ones.
The appliance comparison chart runs the same formula against fixed wattage figures for common household devices (a 10W LED bulb, 50W laptop, 100W TV, 150W refrigerator run continuously, and 1500W space heater) using your entered Hours per Day, Days per Month, and Electricity Rate, so it shows what those reference appliances would cost under your usage pattern rather than typical usage patterns for each device. This calculator does not account for tiered or time-of-use electricity rates, which many utilities use and which can make the true marginal cost of running a device different from the flat rate entered here, nor does it include any fixed monthly service charges on your bill.
Inputs
Results
Monthly Cost
$43.20
How to Use This Calculator
- Enter the device's power consumption in watts (check the label on your appliance).
- Enter how many hours per day the device is used.
- Enter how many days per month the device is used.
- Input your electricity rate in $/kWh — divide your total bill by the kWh used rather than using the headline rate; the US residential average is about $0.18/kWh.
- Review the daily, monthly, and yearly cost, along with the monthly and yearly kWh usage.
- Use the appliance cost comparison chart to see how your device stacks up against common household items.
How the result changes with Power Consumption
| Power Consumption | Monthly Cost |
|---|---|
| 500 | $21.60 |
| 750 | $32.40 |
| 1,500 | $64.80 |
| 2,500 | $108.00 |
What each input means
- Power Consumption
- Check the label on your device for wattage.
- Electricity Rate
- The US residential average is about $0.18/kWh (EIA, mid-2026), but state averages run from roughly $0.11 to over $0.40. Use the effective rate on your own bill: total bill divided by kWh used.
How this is calculated
Formula
Cost = (Watts ÷ 1000) × Hours × Days × Rate per kWh. 1 kWh = 1,000 watts used for 1 hour.Worked example, using the default values
- Identify Input Parameters4 parametersPower Consumption = 1000, Hours Used per Day = 8, Days per Month = 30, Electricity Rate = 0.18 = 4 input(s) provided
- Calculate Monthly CostMonthly Cost43.2 = $43.2
- Calculate Daily CostDaily Cost1.44 = $1.44
- Calculate Yearly CostYearly Cost518.4 = $518.4
Engine last updated . Checked against 1 independently-derived test — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Does doubling the wattage of my device double my Monthly Cost?
Yes — Power Consumption is a direct linear multiplier in this calculator's formula with no caps or adjustments, so doubling watts (holding Hours Used per Day, Days per Month, and Electricity Rate fixed) doubles every cost output exactly. The same is true for proportional changes in any of the other three inputs individually.
Why might my actual bill differ from what this calculator predicts?
This calculator applies one flat Electricity Rate throughout, but many utilities charge tiered rates that rise once you cross a usage threshold, or time-of-use rates that vary by hour of day. It also doesn't include fixed monthly service charges that appear on most electric bills regardless of usage, so the true bill impact of one device can differ from this device-only estimate.
Are the comparison-chart appliances shown using their typical usage or my usage?
Your usage — the comparison chart takes each reference appliance's fixed wattage (10W for an LED bulb, 50W for a laptop, and so on) but runs it through the same Hours Used per Day, Days per Month, and Electricity Rate you entered for your own device, except for the refrigerator row, which always assumes 24-hour, 30-day continuous operation regardless of your inputs.
Is Yearly Cost just Monthly Cost multiplied by 12?
Yes, exactly. Days per Month is treated as a usage pattern rather than a calendar length, so the annual figures apply the same duty cycle you entered — a device you run 10 days a month is costed as 120 days a year, not 365. That means the yearly numbers stay consistent with the monthly ones no matter what you enter, but it also means Yearly Cost is not a calendar-year figure for a device whose usage changes seasonally.
Related Calculators
The questions that sit next to this one — chosen by subject, including calculators filed under a different category.
Carbon Footprint Calculator
Estimate your annual carbon footprint from driving, electricity, heating, and air travel. Compare to US and world averages.
Environmental & SustainabilitySolar Panel Savings Calculator
Calculate solar panel savings, payback period, and return on investment. Includes federal tax credits, production estimates, and 25-year projections.
Electrical & PlumbingAmps / Watts / Volts Converter
Convert between amps, watts, and volts. Enter any two values to calculate the third, plus energy cost estimates.
Crypto MiningMining Electricity Cost Calculator
Calculate monthly and annual power costs from mining rig wattage, electricity rate, and cooling overhead.
Ceramics & PotteryKiln Electricity Cost Calculator
Calculate energy consumption in kWh and electricity cost per kiln firing based on kiln wattage, firing duration, and your electricity rate.
More in Environment, Weather & Climate.