POWER · CALCULATOR

Electricity cost calculator

Free electricity cost calculator: get energy and cost from load power, use per day, number of days and price per kwh. With the formula shown.

Written by Chameera Sampath · Not yet reviewed by a licensed electrician. See the methodology.

US (NEC) only · NFPA 70 / NEC — locally adopted editionDefaults are US values. Verify the locally adopted NEC edition and project data.Official reference ↗

Project inputs

Measurements

Load power

Use per day

Number of days

Price per kWh

currency/kWh

Updates as inputs change. Unit changes preserve the same physical values.

THE MATH BEHIND THE ANSWER

Method & assumptions

Energy = kW × hours × days; cost = energy × tariff

Energy charge only; taxes, demand and fixed charges excluded.

Results do not check every aspect of an electrical installation. The calculators follow US (NEC) practice only; a regional preset changes defaults such as voltage and units, and no result certifies NEC compliance.

Sources and validation →

Worked example

Load power: 2 kW · Use per day: 4 h · Number of days: 30 · Price per kWh: 0.25 currency/kWh

Energy: 240 kWh · Cost: 60 USD

This example uses the stated inputs; results for the entered values appear above.

Explore the power branch →See the related electrical concepts →

Estimating and invoicing tool

Ampxa is developing an estimating and invoicing application for electrical contractors. The list below receives notice when it opens.