How this calculator works
Your bill has two parts: fixed charges you pay no matter what, and charges for each kWh (supply, delivery, riders and taxes). Dividing the whole bill by kWh gives the average rate. Removing the fixed charges first gives the marginal rate — what one more or one less kWh really costs, which is what matters for savings.
Average rate = Bill ÷ kWh
Marginal rate = (Bill − Fixed charges) ÷ kWh
Worked example
Using the default values in the calculator above:
| Input | Value |
|---|---|
| Total electric bill | $145 |
| kWh used on that bill | 820 kWh |
| Fixed monthly charges | $15 |
| Result | Value |
|---|---|
| Marginal rate (each extra kWh) | $0.1585/kWh |
| Average rate (bill ÷ kWh) | $0.1768/kWh |
| Fixed charges share of bill | 10.3 % |
| Cost of 100 more kWh | $15.85 |
| Saved by using 100 kWh less | $15.85 |
Step by step:
- Average = $145 ÷ 820 kWh = $0.1768/kWh
- Marginal = ($145 − $15) ÷ 820 = $0.1585/kWh
Common mistakes to avoid
- Using the “supply” or “generation” rate alone — delivery charges per kWh are often as large.
Frequently asked questions
What is a typical electricity rate in the US?
The US residential average is in the high teens of cents per kWh, but it ranges from about 11¢ to over 40¢ by state. Use your own bill.