Calendar Day and Protocol Index Checker
Distinguish elapsed civil days, inclusive date counts, and day-zero versus day-one indexing.
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Count Gregorian calendar days between fictional dates. No timestamps or patient information.
Calculation results
Elapsed calendar days: 2
Dates counted including both endpoints: 3
End-date index if start is day 0: 2; if start is day 1: 3.
Assumptions and limits
Uses Gregorian dates in years 1000–9999 and UTC arithmetic to avoid daylight-saving offsets. It counts civil dates, not elapsed 24-hour periods between local timestamps. Start and end on the same date give zero elapsed days and one included date. Requires end on or after start. No business-day, month-anniversary, time-zone, partial-date or protocol-specific window rules are inferred. Choose a convention before using it in a study.
Python: Gregorian date arithmetic · Read the practical guide · Download blank worksheet (TXT)