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Electricity Cost Calculator

Estimate the metered energy and variable electricity charge for an appliance or group of identical devices using its actual wattage and your utility rate.

Formula reviewedJuly 24, 2026Inputs stay on your device
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01

What does the electricity cost calculator calculate?

Multiply watts by the number of devices and operating hours, divide by 1,000 to get kilowatt-hours, then multiply by your utility’s current energy rate. This estimates the usage-based charge for the entered equipment; fixed customer charges, tier changes, demand charges, taxes, and cycling can change the bill.

02

Electricity use and variable cost

Monthly kWh = watts × devices × hours/day × days/month ÷ 1,000; monthly cost = monthly kWh × local $/kWh

Dividing watt-hours by 1,000 converts them to kilowatt-hours. The entered utility energy rate then prices only that metered usage, keeping fixed charges and tariff-specific adjustments outside the appliance estimate.

03

How to measure for an accurate estimate

  1. Read input watts from the equipment nameplate or use a suitable plug-in power meter for a representative operating period.
  2. For cycling equipment, divide measured watt-hours by elapsed hours to obtain a realistic average load instead of using peak watts continuously.
  3. Copy the applicable per-kilowatt-hour energy rate from a current utility bill and identify whether time-of-use or tier pricing applies.
  4. Group devices only when their wattage and schedule are genuinely alike; otherwise calculate each load separately.
04

Portable heater used during one month

A 1,500-watt heater runs five hours per day for 30 days, and the customer’s current usage rate is $0.18 per kilowatt-hour.

The heater uses 225 kWh, costing $40.50 for the month and $486.00 over twelve identical months.
05

Before you purchase material

  • Compare energy use at the same operating schedule; lower wattage alone does not prove lower annual cost when runtimes differ.
  • Check ENERGY STAR or manufacturer test data for comparable products, then verify that the test conditions match intended use.
  • Use a utility’s own tariff or online account for current rates rather than a national average that may not apply.
  • Treat claimed bill savings cautiously when they omit climate, behavior, tariff, or equipment-cycling assumptions.
06

Common questions

Where do I find my electricity rate?

Look for the energy or generation charge expressed in dollars or cents per kilowatt-hour on a current bill. If the tariff has tiers or time-of-use periods, run separate calculations for each applicable rate instead of blending unrelated fixed customer charges into the appliance rate.

Why can actual appliance cost differ from this result?

Thermostats, compressors, variable-speed motors, standby modes, weather, and user behavior change average power and runtime. A nameplate often shows maximum input rather than average consumption. Measuring representative use and applying the correct tariff period normally produces a more useful estimate.

Should fixed utility fees be included?

Usually not when estimating the incremental cost of one appliance, because the customer charge may remain even without that appliance. Add fixed fees only when modeling a complete bill, and keep them separate so they are not multiplied by appliance energy use.

Can I compare two appliances with this calculator?

Yes. Calculate each appliance with its own measured watts and realistic runtime while holding the same utility rate constant. Compare monthly kilowatt-hours as well as cost; purchase price, maintenance, useful life, capacity, and performance still belong in the final buying decision.

07

Sources and reference standards

Project workflows

Use this result in a complete project plan

Home energy cost planner

A home-energy plan should begin with measured kilowatt-hours and the tariff that actually prices them, not a national bill or a promised savings percentage. Appliance schedules, electric-vehicle charging, future electrification, solar production and outage loads answer different questions. This sequence keeps energy, power, time and money in their proper units while preserving the source of every assumption.

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