How this calculator works
The formula behind almost every utility bill: usage × rate, plus a fixed service charge, plus percentage taxes and fees. Read the three numbers off last month's bill and this predicts the next one.
- Usage charge = units used × rate per unit.
- Subtotal = usage charge + fixed service charge.
- Estimated bill = subtotal × (1 + taxes & fees % ÷ 100).
Worked example
With these inputs: units used this period 650; rate per unit $0.15; fixed service charge $12; taxes & fees 6%.
The result is estimated bill $116.07, with usage charge $97.50 and fixed charge $12.00.
Units by utility
Electricity is billed in kilowatt-hours (kWh), natural gas in therms or cubic feet (CCF), and water in gallons or hundred cubic feet (HCF). Use the same unit for usage and rate.
If your utility uses tiered rates (a higher price above a certain usage), use a blended rate: the total usage charge ÷ total units from a recent bill.
Budget for seasonal swings
Heating and cooling can double a winter or summer bill. Estimate your highest month, then either budget for it or ask about your utility's budget-billing plan, which spreads yearly costs evenly. Track each utility as its own bill so you can see month-to-month changes.
Frequently asked questions
How can I estimate my electric bill?
Multiply your expected kWh by the rate per kWh, add the fixed monthly charge, then add the tax and fee percentage from your bill.
What is a fixed service charge?
A flat monthly fee for being connected, charged even if you use nothing. It appears on most electric, gas and water bills.
Why is my bill higher than usage × rate?
Fixed charges, delivery or distribution charges, and taxes add to the usage charge. That's why this estimator includes them.