UTC time-of-use calculator: peak windows in UTC
UTC (IANA zone UTC) runs UTC+0 standard time and UTC+0 during daylight saving. UTC never changes for daylight saving, so a peak window entered here stays fixed year-round; it will drift relative to any local clock that does observe daylight saving.
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.
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 "UTC" in the Utility timezone field after opening the calculator.