Electricity Cost Calculator

Enter load watts, daily runtime, days, and rate per kWh to estimate energy use and cost. This does not model utility tariffs or demand charges.

  • Updated August 22, 2026
Inputs
Result

Formulas

  • Daily energy kWh = watts / 1000 x hours per day
  • Total energy kWh = daily energy kWh x days
  • Estimated cost = total energy kWh x rate per kWh

Use this calculator

Estimate kWh and cost from power, runtime, billing days, and a user-entered electricity rate.

Read the result

Review the calculated values with their displayed units and assumptions. The result is a planning aid for the stated inputs, not a final equipment or installation decision.

Check before final work

This is a simple energy-cost estimate. Utility bills can include demand charges, time-of-use periods, taxes, riders, minimum bills, fixed charges, and other tariff rules not modeled here.

FAQs

Where do I find the rate per kWh?

Use the energy rate from a utility bill or published rate schedule. The result is only as accurate as the rate and runtime you enter.

Does this match my full utility bill?

No. It estimates energy charges only and does not include demand charges, taxes, fixed fees, riders, or time-of-use differences.