Effective Rate — Your True Cost Per kWh
Texas Electricity Glossary
The effective rate is the actual average cost you pay per kilowatt-hour, calculated from your real total bill divided by your total kWh consumed. It includes all charges — the REP's energy rate, any fixed base charges, bill credits, and the TDU delivery charge — at your specific usage level. The effective rate is the most honest measure of what a plan actually costs you, and it is almost always different from the advertised rate printed on the plan's marketing materials.
Advertised Rate vs. Effective Rate
Worked Example
Plan advertised at 8.5¢/kWh (at 1,000 kWh, including a $60 bill credit).
You actually use 800 kWh this month. The $60 credit doesn't apply below 1,000 kWh.
Your bill: 800 kWh × 12¢ base rate + $5 customer charge = $101.
Effective rate: $101 ÷ 800 kWh = 12.6¢/kWh — 48% more than advertised.
Why the Effective Rate Matters
Texas electricity providers are required to disclose rates at exactly 500, 1,000, and 2,000 kWh on the Electricity Facts Label (EFL). But few households use exactly these amounts every month. Plans with large bill credits are particularly misleading because the credit inflates the apparent value at the credit threshold while leaving customers at other usage levels with a much higher effective rate.
The core function of TexasPowerCost.com is to calculate the effective rate for any plan at any usage level, using linear interpolation across the three EFL price points. This gives you a much more accurate comparison than the advertised rate.
How to Calculate Your Effective Rate
From your actual electricity bill: Total bill amount ÷ Total kWh consumed = Effective rate (in dollars per kWh). Multiply by 100 to convert to cents per kWh. Make sure to include all line items — energy charge, TDU delivery, any base charges — and subtract any credits applied.
Related Terms
- EFL — the source of the three price points used to estimate effective rate
- Bill Credit — the primary cause of divergence between advertised and effective rates
- Minimum Usage Fee — raises effective rate at low usage levels
- kWh — the denominator in effective rate calculations
- TDU Charge — must be included for a true all-in effective rate
Frequently Asked Questions
What is the effective rate for electricity?
Your effective rate is your total monthly electricity bill divided by your total kWh consumed that month. It captures the real per-kWh cost after all bill credits, base charges, and fees are applied — unlike the advertised rate, which is calculated at a specific usage level (usually 1,000 kWh) and may not apply at your actual usage.
Why is my effective rate different from the advertised rate?
Advertised rates are typically optimized for a single usage level (1,000 kWh). At any other usage, the effective rate changes because: (1) fixed base charges spread over fewer or more kWh, (2) bill credits may or may not trigger depending on your usage, and (3) tiered pricing means the per-kWh rate changes at different usage levels. Plans with large bill credits can have wildly different effective rates just 200 kWh above or below the credit threshold.
How do I calculate my effective electricity rate?
Divide your total monthly bill (including all charges — energy, TDU delivery, base charges, minus any credits) by the total kWh shown on your bill. For example: $142 total bill ÷ 1,100 kWh = 12.9¢/kWh effective rate. TexasPowerCost.com calculates the effective rate for every available plan at any usage level you specify.