US Central time-of-use calculator: peak windows in America/Chicago
US Central (IANA zone America/Chicago) runs UTC-6 standard time and UTC-5 during daylight saving. Follows the same U.S. federal daylight saving schedule as the other continental U.S. zones: forward the second Sunday in March, back the first Sunday in November.
Why the clock matters for TOU billing
A peak window entered as, for example, 4pm to 9pm is evaluated against the local time of whichever timezone you select in the calculator, not your browser's timezone. If a utility's actual peak window shifts with daylight saving, or if the region does not observe daylight saving at all, using the wrong timezone can misclassify an hour of usage as peak or off-peak.
Examples of utilities in this region
- ComEd (IL)
- Xcel Energy (MN)
- CPS Energy (TX)
- Ameren
Names only, for orientation. Always use the peak window and rates from your own current bill or your utility's published tariff, not a figure from this page.
Deep-linking a prefilled scenario is intentionally not supported: this tool keeps share links disabled by design so a URL never carries entered usage or rate data. Select "America/Chicago" in the Utility timezone field after opening the calculator.