Updated November 6, 2026
Start with the billing period
Look for the service dates near the top. Billing periods are not calendar months. One bill might cover 28 days and the next 34, and those six extra days can add more than 20% to your usage with no change in how you live. Before comparing two bills, divide each one's kWh by its number of days. That daily figure is the fairest way to compare them.
Find your kWh
A kilowatt-hour is the unit you are billed for. A 1,000 watt space heater running for one hour uses 1 kWh. Your bill usually shows a previous meter reading, a current reading and the difference between them. Many bills also include a small bar chart of the past 13 months, which is the quickest way to see whether this month is really unusual or just the same month it always is.
Check whether the read was actual or estimated
Look for a small label such as "actual", "estimated" or the letter E beside the meter reading. When a utility cannot get a reading it may estimate one. If that estimate was too low, a later actual read catches up, and the correction lands on one bill. Two low months followed by one huge month is the classic pattern. If you have a smart meter, estimated reads should be less common, but they can still happen.
Separate supply from delivery
Many bills split charges into two groups:
- Supply or generation: the cost of the electricity itself. In states with retail choice, you may buy this from a separate company at a plan rate, and that rate can change when a fixed term ends.
- Delivery or distribution: the cost of moving electricity over poles and wires to your home. This is set through regulators and your utility, and you cannot shop for it.
If your total went up and usage did not, compare these two groups first. It tells you whether to look at your supply plan or at a utility rate change.
Fixed charges, riders and taxes
A customer or basic service charge is billed whether you use any power or not. Riders are smaller line items, often named for fuel, storm recovery or efficiency programs, that utilities add or adjust between full rate cases. Taxes come last. Individually these lines look small, but a new or increased rider can explain several dollars of change.
Tiers and time-of-use rates
Some plans charge more per kWh once you pass a monthly threshold. Others charge more during peak hours. On a tiered plan, a hot month costs more than usage alone suggests because extra kWh land in the pricier tier. On a time-of-use plan, the same usage can cost more if it shifts into peak hours. Your bill should name your rate schedule, and your utility's website will explain it.
What to compare, in order
- Days in each billing period.
- Total kWh, then kWh per day.
- Whether either read was estimated.
- Your all-in price: total dollars divided by total kWh.
- Supply lines, delivery lines and any new rider.
Those numbers are also what our bill comparison tool needs. Enter both bills and it estimates how much of the change came from price, weather and other usage.
Common questions
Where do I find kWh on my bill?
Look in the usage or meter section. It is usually shown as the difference between the previous and current meter readings, and it may be repeated near a usage chart.
What does an estimated read mean?
The utility did not get an actual meter reading for that period and billed from an estimate. A later actual read corrects any difference, which can make one later bill unusually high or low.
Why are there two sets of charges?
Many bills separate the electricity itself (supply) from the cost of delivering it (delivery). Comparing the two tells you which one changed.
How do I work out my real price per kWh?
Divide the total bill by total kWh. This all-in price includes fixed fees and riders, so it is usually higher than the rate printed on the bill.