Calculators

How these tools fit together

The six calculators each answer one question, and they do not share a hidden total. A tariff line is a schedule with an effective date. An EIA-861 figure is what residential customers paid across 2025. When both exist, the page shows them next to each other. It never adds them.

Start with the bill calculator when you have a utility in mind. Pick a state, optionally a county from the EIA Form 861 service-territory file, then the utility. If a residential sheet was checked, you get that sheet's math for the kilowatt-hours, month, and billing days you enter, plus the EIA all-in average for the same kilowatt-hours. The coverage note on a tariff total says which taxes, riders, or retail energy charges were left out.

The appliance tool prices a median annual kilowatt-hour figure from an ENERGY STAR certified-product list, or a nameplate wattage times hours. The rate starts at the U.S. residential average, and you can replace it with a utility rate from the bill calculator. The EV tool prices a fueleconomy.gov combined rating for the miles you enter, at a home rate and a public rate, and sets that next to a gasoline car at the miles-per-gallon you enter. The heating tool prices the same delivered Btu four ways: electric resistance, a heat pump at the HSPF2 you enter, a gas furnace, and a propane furnace, using EIA prices for the state you pick.

The Texas plan checker reads one Power to Choose export. It flags an offer when the file lists a minimum-usage fee or credit, when the fees and credits field is not empty, or when the 500 kWh price is more than 15 percent above the 1,000 kWh price. The estimate multiplies your kilowatt-hours by the nearest of the three disclosed prices. It does not rebuild the retailer's tariff. The rate-history tool plots one utility's annual residential cents per kilowatt-hour from 2015 through 2025, using residential revenue divided by residential sales for each year.

Use the methodology page when you want the formula rather than the result. Cents per kilowatt-hour on a utility page is residential revenue divided by residential sales. State averages come from the Average Bill file in EIA Form 861, not from summing utility rows. Guides cover how to read a bill, how an all-in price differs from an energy charge, and how a Texas bill credit can make a low 1,000 kWh price a poor guide to a smaller month.

Calculator inputs stay in the browser. Choosing a utility loads a data file that shipped with the site. There is no account. If a total does not match the document it cites, the document controls. Send the page URL and the line you checked through the contact page.