Compare a hypothetical shift, including time before and after, with an availability window. The result is a time comparison, never an approval or accept/decline recommendation.
Use invented times and durations. No names, employer details, account information or locations. The calculator sends and saves nothing.
Window: 0.25–48 hours. Shift: 0.25–24 hours. Use quarter-hour duration steps. Allowances: 0–240 whole minutes each. All times share one clock; no time-zone or daylight-saving adjustment.
Enter hypothetical values, or load the invented example.
How the model works, with or without JavaScript
Availability end = availability start + window length.
Left margin = required departure − availability start.
Right margin = availability end − estimated return.
Both margins must be zero or positive for a mathematical fit. A negative margin marks a conflict on that side. Margins cannot be exchanged between edges.
Invented example: availability 1:00–11:00 p.m. on Day 0; shift 3:00–9:00 p.m.; 45 minutes before and 30 minutes after. Required departure is 2:15 p.m.; return is 9:30 p.m. Left margin: 75 minutes. Right margin: 90 minutes.
Limits: no real dates, time zones, daylight-saving transitions, pay, overtime, rest compliance, fatigue, qualifications, permissions or live scheduling. Window lengths are model inputs, not recommended working or rest durations. If actual timing crosses a clock change, use verified dated times elsewhere.