Method

How the overlap calculation works.

Overlap Days converts every person's repeating code sequence into dated work intervals, combines those intervals, and measures the remaining common gaps.

1. Cycle anchoring

Each pattern begins on a user-selected cycle day 1. For example, D D N N O O O O means two day shifts, two night shifts and four off days before repeating. Different people can use different start dates and cycle lengths.

2. Overnight intervals

When a shift end time is earlier than or equal to its start time, the tool treats the end as occurring on the following date. A 19:00–07:00 night shift therefore occupies both calendar dates.

3. Recovery after nights

Recovery hours are appended only to N shifts. This is a planning assumption, not a medical recommendation. Set it to zero when you only want literal roster overlap.

4. Common free time

The planner merges all participants' busy intervals. Shared time is the complement of that combined timeline. Summary hours are measured from 06:00 to midnight, while a strict full day requires the entire calendar date to remain free.

5. Threshold labels

LabelRule
Full dayNo scheduled work or night-recovery interval touches the date.
Shared eveningAt least four common hours between 18:00 and midnight.
Daytime windowAt least four common hours between 09:00 and 18:00.

What is deliberately excluded

Public holidays, leave, overtime, sickness, swaps, travel time, childcare, sleep outside the configured night-recovery period and employer-specific rules are not automatically modelled.