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Power Consumption Calculator

Estimate the electricity usage and cost for any appliance or device. Add up to 8 devices, enter wattage and usage hours, and instantly see daily, monthly, and yearly cost breakdowns.

US average: ~$0.16/kWh

How Energy Cost is Calculated

kWh/day = (W × hrs/day × days/wk) / (1000 × 7) Daily energy normalised over 7 days per week
kWh/month = kWh/day × 30.44 Average month = 30.44 days
kWh/year = kWh/day × 365 Annual energy consumption
Cost = kWh × rate ($/kWh) Multiply energy by your utility rate

How to Use the Power Consumption Calculator

  1. 1
    Set Your Electricity Rate
    Enter your rate in dollars per kWh. Check your utility bill or use the default US average of $0.12/kWh.
  2. 2
    Add Your Devices
    Enter a name (optional), wattage, hours used per day, and days per week for each device.
  3. 3
    Add More Devices
    Click "Add Device" to include up to 8 appliances in a single calculation.
  4. 4
    View Breakdown
    See energy (kWh) and cost per device plus grand totals in a clear table.

Example Calculation

A 1,500W space heater used 6 hours/day, 5 days/week at $0.15/kWh:

kWh/day = (1500 × 6 × 5) / (1000 × 7) = 6.43 kWh/day
kWh/month = 6.43 × 30.44 = 195.7 kWh
Monthly cost = 195.7 × $0.15 = $29.36/month
'What uses the most electricity at home?', 'answer' => 'Heating and cooling (HVAC) typically accounts for 40-50% of home electricity use. Water heaters, electric dryers, and ovens are also major consumers. Lighting, TVs, and electronics each account for a relatively small share — though they add up if left on continuously.'], ['question' => 'How can I reduce my electricity bill?', 'answer' => 'The most impactful steps are: upgrade to a programmable thermostat, switch to LED lighting, unplug devices on standby (phantom loads), run dishwashers/laundry during off-peak hours, and ensure your home is well-insulated. Energy Star-rated appliances also consume significantly less power.'], ['question' => 'What is a kWh in simple terms?', 'answer' => 'A kilowatt-hour is the energy used by a 1,000-watt (1 kW) appliance running for one hour. For example, a 100W light bulb running for 10 hours uses 1 kWh. A 2,000W microwave running for 30 minutes also uses 1 kWh.'], ['question' => 'Does standby power consumption matter?', 'answer' => 'Yes — devices in standby or "off" modes still draw power, collectively called phantom or vampire loads. A single device may only draw 1-5W, but the average home has dozens of such devices. Together they can add up to 5-10% of total electricity consumption annually.'], ]" />

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