Rate source and dates
Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, released 2026-09-24. We use the Residential columns for all 50 states, the District of Columbia, and the U.S. Total.
- Observation month: July 2026.
- Comparison month: July 2025.
- Source release date: 2026-09-24.
- Last successful verification: 2026-10-08.
- Units: cents per kilowatt-hour (¢/kWh).
The check date is not a claim that the data describe today. Reporting lags and later revisions are possible. We do not turn missing months into a continuous time series.
What “average price” means
EIA average retail price is reported electricity revenue divided by electricity sales. We use EIA’s national figure, not the arithmetic mean of state averages. These are historical residential averages, not supplier quotes, utility tariffs, or guaranteed marginal costs. Reported revenue can embed charges that differ from a tariff’s energy-only rate.
Formulas
- Watts to energy: daily kWh = watts ÷ 1,000 × scheduled hours × active percentage ÷ 100.
- Month: daily kWh × days used per month × dollars per kWh.
- Year for power-based tools: monthly cost × 12. This repeats the selected month’s usage; it is not automatically 365 days of use. Seasonal appliances need a seasonal interpretation.
- Annual-label tools: annual cost = annual label kWh × rate. Monthly = annual ÷ 12; daily = annual ÷ 365.
- Per-cycle tools: monthly cost = kWh per load × monthly loads × rate. Annual = monthly × 12. A daily average uses a 30-day month.
- EV, battery input: wall kWh = battery kWh ÷ (1 − wall-energy loss fraction). Cost = wall kWh × rate.
- EV, wall input: cost = metered wall kWh × rate, without adding losses again.
- Comparison: calculate A and B with their own power and hours, a shared number of days and rate, then subtract. The displayed difference is absolute and names the lower-cost option.
Units: 100¢ = $1, so 20¢/kWh = $0.20/kWh. Calculations retain full numerical precision; dollar outputs are rounded to cents for display. A displayed $0.00 can be a nonzero amount below half a cent.
Inputs, scenarios, and exclusions
Appliance watts, hours, active percentages, 500 annual kWh, 3 kWh per load, and 50 charging kWh are editable examples. They are not market averages. The EV 10% loss is an illustrative assumption; actual losses vary. Savings scenarios keep the other inputs fixed and do not predict changes in comfort or performance.
The single-rate appliance tools do not separately model fixed charges, taxes, time-of-use periods, tiers, minimum bills, demand charges, utility discounts, gas, equipment purchase, maintenance, or installation. The dedicated time-of-use and bill tools cover the limited additional items described below. If you enter a bill-derived blended rate, some fees may already be embedded. Use the applicable variable supply and delivery rate for an incremental appliance estimate.
Time-of-use and bill comparison
Time-of-use: peak kWh × peak price + off-peak kWh × off-peak price + fixed fee. Shifting moves kWh between periods while holding total use constant. The comparison includes a separate fixed fee for the flat plan and solves for the break-even peak share. A threshold outside 0–100% means the plans do not cross within that range.
Bill analyzer: period kWh × variable price + other charges. The difference is decomposed in the order billing days, daily kWh, per-kWh price, and other charges. The components reconcile before rounding. This is an order-dependent mathematical allocation, not a diagnosis of appliance or weather effects. Neither tool implements a full utility tariff.
How updates work
This version serves a saved, validated snapshot. It does not call EIA whenever a visitor opens a page, and it has no API key. An update retrieves EIA’s public table, verifies the unit and period, checks all 51 jurisdictions and the national row, and rejects malformed, duplicate, missing, or backward-period data. Only a successful check replaces the snapshot. The original source is retained with a checksum for review.
Update status: manual refresh workflow available; unattended scheduling is not enabled. A successful refresh must be reviewed and published before it appears here. If an update fails, the last verified data and its original check date remain visible.
Reuse and independence
EIA’s Copyrights and Reuse policy permits use of its public-domain data with source and publication-date acknowledgment. We do not use EIA’s protected logo or third-party photographs, and we do not imply government endorsement. Its free API is subject to separate API terms; this version uses the public report table.