Ameren electric rates in Missouri and Illinois

Ameren's price per kWh in each state, by period

Ameren is a holding company with two operating utilities that EIA reports separately: Ameren Missouri (legally Union Electric Company) and Ameren Illinois (Ameren Illinois Company). Each has its own tariff, approved by its own state commission, so "Ameren rates" has two answers. EIA measures them as average revenue per kWh: everything residential customers were billed, customer charge, energy, delivery and riders, divided by the kWh they used. For Ameren Illinois the figure covers only homes that also buy their supply from Ameren.

The single month is a summer reading and sits above both 12-month figures; for comparing the two utilities, the year or the 12 months is the fairer basis. On the 2025 figures, the two Ameren utilities averaged 14.35¢ per kWh¹ together, weighted by kWh.

Ameren Missouri (MO)13.26¢

Ameren Illinois (IL)16.70¢

Source: EIA-861 annual electric power industry report, 2025 final. EIA-861 2025 final. Average revenue per kWh is all charges divided by kWh; it is not a tariff rate.

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Utility	average residential price (bundled customers)
Ameren Missouri (MO)	13.26¢
Ameren Illinois (IL)	16.70¢

Each utility was close to its own state's average. Ameren Missouri was 0.3% below the Missouri average in 2025, and Ameren Illinois 5.5% below the Illinois average. The gap between the two is mostly the gap between Missouri and Illinois: Missouri's statewide residential average (13.30¢ per kWh) ranked 13th lowest among the states in 2025, Illinois's (17.67¢ per kWh) 17th highest⁴. Nationally, among the 177 utilities with 100,000 or more residential customers, Ameren Missouri placed 44th lowest of 177 and Ameren Illinois 63rd highest of 177¹.

A cheaper kWh, a bill only a little smaller

Ameren Missouri's price advantage shrinks on the bill because its homes use more electricity. In 2025 the average Ameren Missouri home used 1,032 kWh a month and paid $136.92; the average full-service Ameren Illinois home used 888 kWh and paid $148.32¹. Over the last 12 months (September 2025 to August 2026) the bills were $142.30 and $153.06².

Ameren Illinois (IL)888

Ameren Missouri (MO)1,032

Source: EIA-861 annual electric power industry report, 2025 final. EIA-861 2025 final. Average revenue per kWh is all charges divided by kWh; it is not a tariff rate.

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Utility	average monthly residential use
Ameren Illinois (IL)	888
Ameren Missouri (MO)	1,032

The two also peak in different seasons. In EIA's monthly data for September 2025 to August 2026, Ameren Missouri homes used the most in January 2026, 1,404 kWh on average, for a bill of $146.25. Ameren Illinois homes peaked in July 2026 at 1,193 kWh, with an average bill of $232.34 that month. The smallest monthly bills were $87.04 in Missouri (October 2025) and $115.79 in Illinois (April 2026²). Missouri's winter peak in kWh did not produce its largest bill: winter kWh there cost less on average than summer ones, so Ameren Missouri's summer bills ran well above its January one; the Ameren Missouri page shows the months side by side.

Illinois prices rose faster, in 2025 and again in 2026

From 2024 to 2025, Ameren Illinois's full-service average rose 9.4%, from 15.26¢ per kWh to 16.70¢ per kWh, and its average bill +13.9%. Ameren Missouri's average rose 5.6%, from 12.56¢ per kWh to 13.26¢ per kWh, and its bill +10.2%. In both, the bill grew faster than the price because use per home also went up: from 853 kWh to 888 kWh a month in Illinois and from 989 kWh⁵ to 1,032 kWh¹ in Missouri.

The pattern held into 2026. Comparing August 2026 with August 2025, the residential average was +8.9% at Ameren Illinois and +3.6%² at Ameren Missouri, against +7.2% for Illinois and +4.6%³ for Missouri as a whole. These monthly figures are preliminary until EIA's final annual survey.

Ameren IllinoisIllinois average, all providers

Source: EIA-861M monthly sales and revenue by utility; EIA, Electric Power Monthly / EIA-861M sales and revenue by state. Residential revenue divided by kWh in each month, as reported to EIA's monthly survey (EIA-861M; months since January 2026 preliminary). Bundled (default-service) customers only.

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Month	Ameren Illinois (¢/kWh)	kWh per customer	Bill per customer
January 2025	12.93¢	1,105	$142.87
February 2025	14.50¢	992	$143.88
March 2025	17.19¢	733	$125.99
April 2025	18.85¢	596	$112.29
May 2025	16.99¢	629	$106.84
June 2025	15.98¢	968	$154.65
July 2025	19.22¢	1,183	$227.30
August 2025	17.84¢	1,040	$185.55
September 2025	20.52¢	805	$165.20
October 2025	20.51¢	706	$144.83
November 2025	17.09¢	702	$120.02
December 2025	12.28¢	1,184	$145.32
January 2026	11.06¢	1,133	$125.23
February 2026	18.13¢	840	$152.26
March 2026	18.61¢	704	$131.00
April 2026	19.75¢	586	$115.79
May 2026	18.49¢	683	$126.26
June 2026	18.36¢	923	$169.52
July 2026	19.47¢	1,193	$232.34
August 2026	19.42¢	1,054	$204.63

Rate requests and decisions are public. Ameren Missouri's go to the Missouri Public Service Commission, Ameren Illinois's delivery cases to the Illinois Commerce Commission. The guide to rate increases explains how a case reaches a bill.

One market with choice, one without

The biggest difference between the two utilities is who sells the electricity. Missouri has no residential retail choice: in 2025, 0 homes in the state bought power from an alternative supplier, so all 1,100,654¹ Ameren Missouri residential customers bought both supply and delivery from Ameren.

In Illinois, 475,151 of the 1,062,810 homes on Ameren's wires, 44.7%, bought supply from a competitive supplier or a municipal aggregation program in 2025. For them Ameren billed delivery only, an average of 8.77¢ per kWh or $76.67 a month; their supplier billed for the power separately. That delivery-only figure is one part of a bill, and the 16.70¢ per kWh¹ full-service average a whole bill: they describe different customers and are never added together.

Customers weighing an Illinois supply offer compare it with the Price to Compare, the supply and transmission charges of Ameren Illinois's default service, which the Illinois Commerce Commission publishes on Plug In Illinois. For November 2026 it was 10.441¢ per kWh, against 8.402¢ per kWh⁶ for the same month a year earlier. It is a current price for supply and transmission only, so it does not line up with any of the full-service averages above. The Illinois retail choice guide covers how it works.

Time-of-use in Missouri, rooftop solar in Illinois

Both utilities had advanced meters on practically every home in 2025 (99.9% in Missouri, 99.9% in Illinois), but they use them differently. Ameren Missouri reported 931,654 homes on time-of-use pricing, 84.6% of its residential customers. Ameren Illinois reported 168,050, 15.8%, on real-time pricing and critical peak rebates⁷. EIA records enrollment only; the hours and prices are in each utility's tariff.

Rooftop solar runs the other way. Ameren Illinois had 39,801 net-metered residential installations (437.8 megawatts) in 2025, 37.4 per 1,000 residential customers. Ameren Missouri had 8,998 (85.1 megawatts), or 8.2⁷ per 1,000.

Outages: storms made the Missouri total

Counting every event, Ameren Missouri customers averaged 594 minutes without power in 2025, about twice Ameren Illinois's 287 minutes. Leaving out major event days, the days of unusually widespread outages that utilities report separately under IEEE 1366, the order reverses: 119 minutes in Missouri and 130 minutes in Illinois. Customers had a similar number of interruptions in each, 1.18 and 1.19⁸ on average including major events.

Businesses, counties and help with bills

Business prices differ less at the industrial end. In 2025, Ameren Missouri's full-service commercial customers paid an average of 10.29¢ per kWh and industrial customers 8.19¢ per kWh; at Ameren Illinois the figures were 14.60¢ per kWh and 7.63¢ per kWh¹, for the businesses that still bought supply from Ameren.

Ameren Missouri reported customers in 65 Missouri counties and Ameren Illinois in 81⁹ Illinois counties. In nearly all of them, cooperatives, city utilities or other companies also serve customers, so the county does not decide which utility, or which price, applies to a home; each utility's service map does, by address. EIA publishes no price for a city or ZIP code.

Households struggling with bills can apply for federal energy assistance through their state: Missouri's LIHEAP allocation for fiscal 2026 was $92.4 million and Illinois's $199.8 million¹⁰. Each utility page has the full detail, and the Missouri and Illinois pages place Ameren among the other utilities in each state.