Monthly Electricity Cost
Calculator

Inputs

Monthly energy (kWh)
840

Results

Monthly energy (kWh)
840
Energy charge
142.8
Monthly bill
154.8
Annual bill
1,857.6

Energy results

Monthly energy (kWh)840
Energy charge142.8
Monthly bill154.8
Annual bill1,857.6

formula-map diagram

Monthly energy (kWh)
840
Energy charge
142.8
Monthly bill
154.8
Annual bill
1,857.6

Energy relationship

Formula

Bill = daily kWh × days × price + fixed fee

= 840

Note

This is a simplified model: it applies the standard equation to the numbers you entered and ignores real-world losses, weather variation, tariff structures and equipment tolerances. Wind power assumes air density 1.225 kg/m³ at ISA sea level and the power coefficient you enter (Betz limit 0.593). Verify with measured data or a professional energy audit before making purchasing decisions.

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Frequently asked questions

What's the simplest way to estimate my monthly cost?+

Multiply your total expected kWh usage for the month by your electricity rate per kWh, adding any fixed monthly service charges your utility applies separately from usage. If you have multiple devices, sum each one's individual kWh contribution first.

Why is my actual bill different from this estimate?+

Utilities often use tiered pricing (higher rates after a usage threshold), time-of-use rates that vary by hour, seasonal rate changes, and additional fees like taxes or delivery charges, none of which a flat-rate estimate captures. This calculator gives a baseline, not a bill-matching prediction.

How much does seasonal usage change my monthly cost?+

Heating and cooling loads swing dramatically by season, so a household's electricity use, and cost, can be 2-3 times higher in peak summer or winter months compared to mild spring or fall months, even with identical rates.

Can I use this to compare different electricity rate plans?+

Yes, running the same estimated usage through different per-kWh rates (and accounting for any fixed charges) is a straightforward way to compare flat-rate, tiered, or time-of-use plans, as long as you estimate your usage pattern realistically for time-of-use comparisons.

What's the best way to get an accurate usage figure to plug in?+

Check your smart meter or utility app for actual historical kWh usage, which is far more reliable than adding up estimated appliance wattages. If those aren't available, summing your major appliances' individual energy costs gives a reasonable approximation.