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ENERGY CALCULATOR

Electricity bill

Estimate a monthly electricity bill from power consumption and tariff. Enter your own values, then select Calculate to see the result.

Reviewed Oct 15, 2026Formula shownRuns in your browser

Your inputs

Change any value. Use one currency consistently for all money fields.

W
hours
days
/kWh

Enter your numbers, then tap Calculate.

The currency selector changes the displayed symbol only. It does not convert exchange rates.

Your result

A transparent estimate based on the assumptions you enter.

Estimated monthly bill
—
Estimate only. Check the explanation and limitations below.
FormulaMonthly cost = (watts ÷ 1,000) × hours per day × days × electricity rate per kWh.

What this result means

The result estimates the variable energy charge for the usage you entered. It does not automatically add standing charges, taxes, demand fees, or tiered tariff adjustments.

How the electricity bill calculator works

Electricity use is power in kilowatts × hours × days. Use the rate from your own utility bill; taxes and fixed fees are excluded.

The calculator does not fetch live prices or rates. That is intentional: you provide the tariff, price, rate or cost that actually applies to your situation, which makes the assumptions visible and avoids presenting stale market data as current.

How to get a more useful estimate

  • Use the appliance’s measured average power when available, not only its maximum nameplate rating.
  • Enter the energy rate from your own bill in the same currency you want the result displayed in.
  • For several appliances, calculate each one separately and add the results or use the appliance annual-cost tool.

Scenario check

For a more realistic household estimate, calculate high-consumption devices separately and compare the total with a recent bill. If the estimate is much lower, fixed charges, tariffs, cycling behavior or uncounted loads may explain the gap. This comparison can help you identify which assumptions deserve measurement instead of simply increasing every wattage estimate.

Important limitations

  • Fixed utility charges and taxes are excluded.
  • Time-of-use, tiered, or prepaid tariffs may require a blended average rate.
  • Appliances that cycle on and off may consume less than their rated wattage.
Planning note: SmartCostTools provides educational estimates, not personalized financial, tax, legal, engineering, energy, lending or professional advice. Verify major decisions with current local information and qualified professionals where appropriate.

Frequently asked questions

Why divide watts by 1,000?

Electricity bills normally price energy in kilowatt-hours. Dividing watts by 1,000 converts watts to kilowatts before multiplying by operating hours.

Can I use my local electricity tariff?

Yes. Enter your own local cost per kWh and choose the currency symbol you want displayed. The calculator does not convert currencies or fetch tariffs automatically.

Why can my bill be higher than this estimate?

Actual bills can include fixed charges, taxes, estimated readings, losses, tiered pricing, or other fees that are outside this simple usage calculation.