Date calculators · Workdays & planning
On-Call Rotation Calculator
Build an all-day on-call roster with named people, rotation length and unavailable dates. See substitutes, uncovered dates and each person's coverage load.
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Choose your dates.
Select your counting rules and calculate.
Calculation details
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How to use this calculator
Set the planning range, rotation anchor and days per rotation. Add people in rotation order and their inclusive unavailable ranges. Calculate and export the assignments.
Nominal rotation follows the anchor even before it. On an unavailable date, the next available person in rotation order substitutes. Partial absences split assignments; if nobody is available, that date remains uncovered. The fixed order is deterministic, not a fairness optimizer.
A worked example
In an Alex–Sam weekly rotation anchored November 2, 2026, Alex normally covers November 2–8. If Alex is unavailable November 4, Sam substitutes that date and Alex resumes November 5.
Can I schedule timed handoffs?
This version assigns whole calendar dates and exports all-day coverage. Timed handoffs, escalation rules and notifications are outside this tool. Coverage and weekend counts help you review the resulting load.
Further reading: Source workflow and conventions. Your entered rules determine this result.
Which calendar and years are supported?
Use Gregorian dates from 1900 through 2100, with results inside that range. Most daily plans are limited to 366 dates; academic terms and sprint plans allow up to 731. Forms limit the number of entries to keep calculations responsive. Holidays and policy rules come from your inputs. Date-only plans ignore DST; tools with time-zone inputs use the browser's time-zone data and explicitly resolve repeated times. Calendar exports preserve date-only markers or exact timed events as appropriate. Calculations run only when requested, without background polling.
What happens to my dates?
Calculations run on your device. Saving a calculation is optional and keeps it in this browser. A setup link contains the dates and settings you entered; anyone with the link can read them. Use one tab per saved calculator. Clear saved data from Privacy & settings.