Guide · Updated August 12, 2026

Read a utility bill before estimating home-charging cost

A charging estimate usually starts with one number: price per kWh. The difficult part is choosing the number that actually matches your bill. This guide uses a repeatable process rather than a national average.

1. Find the billing period and energy use

Locate the number of days covered and total kWh. A short billing period, extreme weather, or a one-time adjustment can make a single bill unrepresentative. Keep two or three recent bills when possible.

2. Separate fixed charges from energy charges

Most bills include charges that do not rise with each kWh, plus charges that do. For a marginal charging estimate, the energy and delivery charges that change with consumption are usually the relevant starting point. A fixed customer charge still matters for the household budget, but it normally would be paid even without an EV.

3. Check whether time of use applies

If the rate varies by time, calculate at least two scenarios: the price during your planned charging window and the price during expensive hours. Do not use an overnight rate unless you can actually charge overnight.

4. Add a transparent loss assumption

Electricity drawn from the wall is higher than energy stored in the battery because charging is not perfectly efficient. Rather than hide that difference, state the assumption beside the result. If the charger, vehicle, or local climate changes, revisit it.

5. Keep the evidence with the result

Record: bill month, rate plan, energy price, delivery price, charging window, and any apartment or network fee. That short record makes the result understandable months later.

Useful primary references

• U.S. Department of Energy: electricity as a vehicle fuel
• U.S. Department of Energy: understanding utility bills

Sources are provided for background. Your own utility tariff is the controlling source for your price.