Electricity cost calculator

How to calculate an electric bill

An electric bill is the kWh used times the price per kWh, plus any fixed monthly customer charge. Most residential tariffs add several per-kWh lines (generation or supply, transmission, distribution, riders and taxes); add them together to get one price per kWh before you multiply.

1. Find the kWh used on the bill (current read minus previous read).
2. Add every per-kWh charge to get the price per kWh. A price in cents divides by 100 to get dollars.
3. Multiply: kWh × price per kWh.
4. Add the fixed monthly charges (customer, service or meter charge).

Worked example. 1,000 kWh on a tariff with 14.2¢ per kWh in total energy and delivery charges and a $12.50 customer charge: 1,000 × $0.142 = $142.00, plus $12.50 = $154.50. The all-in price is 15.45¢ per kWh, a little above the per-kWh charge because of the fixed fee. Load it with the first quick button in the calculator.

Electricity expense calculator by usage and state

The table runs the calculator for common usage levels at each state's average price over Sep 2025–Aug 2026.^[eia861m] Use it as an electricity expense calculator for budgeting a move or a new appliance; the electricity rates by state table has every state.

Because state averages already include fixed charges, the table slightly overstates low-usage bills and understates high-usage bills in states with large customer charges. For a precise figure, enter your tariff's per-kWh charges and its fixed charge separately.

Gas bill calculator

The same arithmetic works for a natural gas bill: therms × price per therm + fixed charge. A therm is 100,000 Btu.^{[btu][ngheat]} If your bill shows CCF or Mcf instead, multiply CCF by the therm factor printed on the bill (EIA's 2025 state averages for delivered gas run from 917 Btu per cubic foot in Hawaii to 1,096 in Washington, so one CCF holds about 0.917 to 1.096 therms) to get therms. The U.S. average residential gas price was $1.58 per therm over Sep 2025–Aug 2026, and the average customer used 54 therms a month across the whole year.^{[ngprice][ngcons][ngcust][ngheat]} State figures are on the average gas bill page.

Mistakes that make bill estimates wrong

• Using only the supply rate. A supplier's advertised rate covers supply; the utility still charges delivery per kWh on top.
• Counting the fixed charge twice. State average prices already include it.
• Using a summer month for a yearly budget. Multiply 12 months of kWh, not one peak month by 12; the average electric bill page shows how far summer and spring differ.
• Mixing cents and dollars. 15¢ per kWh is $0.15; 1,000 kWh at 15¢ is $150, not $15,000.
• Guessing appliance use. Watts × hours ÷ 1,000 gives kWh; the kWh calculator does it per device.

Tested: the calculator's math (usage × price + fixed, never below zero, inputs limited to 0–100,000 kWh, 0–150¢/kWh and $0–200 fixed) is covered by automated tests with hand-worked examples, including the 1,000 kWh example above.