By EV Charge Cost Editorial Team. Published September 28, 2026, updated October 26, 2026.
How tiered rates work
With a tiered or "increasing block" rate, the first block of kWh each month is billed at a lower price and anything above it at a higher price. Some utilities have two tiers, some more, and the allowance can change by season or climate zone. A few utilities use the reverse, a declining block, where extra kWh get cheaper.
The key point for EV owners: the cost of charging is set by the tier the extra kWh fall into, not by the average on your bill.
A worked example
All tier prices and the allowance in this section are an illustration, not any utility's tariff. We set a 500 kWh monthly allowance, a first-tier price 15% below the U.S. average of 18.16¢/kWh (15.44¢/kWh), and a second-tier price 30% above it (23.61¢/kWh). The EV adds 377 kWh a month, which is 1,125 miles in a 33.5 kWh/100 mi car.
| Household | Base kWh/month | Bill before | Bill with EV | Added by EV | Effective EV rate |
|---|---|---|---|---|---|
| Small home, below allowance | 350 | $54.03 | $130.77 | $76.74 | 20.36¢/kWh |
| Mid-size home (example) | 600 | $100.79 | $189.79 | $89.00 | 23.61¢/kWh |
| Large home | 1,000 | $195.22 | $284.22 | $89.00 | 23.61¢/kWh |
In the mid-size example, the EV adds $89.00 a month. At a flat 18.16¢/kWh it would add $68.46. The difference, $20.54 a month or $246.47 a year in this illustration, comes entirely from where the EV's kWh fall on the tier ladder.
The small home shows the other side: some of its EV energy fits inside the cheaper allowance, so its effective EV rate is lower than the large home's.
How to check your own tiers
- Find the tier allowance and prices on your bill or your utility's rate schedule. The bill often shows how many kWh were billed in each tier.
- Estimate the EV's monthly kWh: miles per month × kWh/100 mi ÷ 100. Your car's rating is on its vehicle page.
- Add that to a typical month's usage and see how much lands above the allowance.
- Divide the added cost by the added kWh. That is your effective EV rate; use it in the calculator.
- Do it for a high-use and a low-use season if the allowance changes.
Ways around the top tier
- Ask about EV or time-of-use plans. Many utilities that use tiers for standard service offer an EV or time-of-use plan without tiers. Compare the whole household bill, not just the EV part. See time-of-use rates and EV charging.
- Look for a separate EV meter option. Some utilities bill a dedicated EV circuit separately, which can keep the car's energy out of the household tiers.
- Cut other household use. Every kWh saved elsewhere drops out of the top tier first.
- Use free or workplace charging when it is convenient. Energy that never reaches your meter never reaches the top tier. See free EV charging.
Declining block rates
Some utilities use the opposite structure: a higher price for the first block and a lower price after it. Under that design the EV's extra kWh are cheaper than your average, which works in your favor. The same method applies: find which block the added kWh fall into and use that price.
Where state averages fit in
The EIA state averages on our state pages blend all tiers and plans together, so they are a reasonable starting point. On a steep tiered plan, your EV's true rate can be noticeably higher; on a well-chosen EV plan, lower.