Shift Calculator

Shift work is any work schedule that falls outside the traditional 9-to-5 daytime window. The Bureau of Labor Statistics reports that approximately 16% of US workers have non-daytime schedules. Common shift patterns include fixed shifts (always the same hours), rotating shifts (cycling through different shifts), and split shifts (working two separate blocks with a long break). Night shifts present a unique calculation challenge because they cross midnight. A shift from 22:00 to 06:30 spans two calendar dates. The standard approach adds 24 hours (1440 minutes) to the end time when it is less than or equal to the start time, then calculates the difference normally. Gross shift time is the total elapsed time from start to finish. Net shift time subtracts scheduled breaks. The distinction matters for payroll: paid break time should remain in gross hours, while unpaid breaks must be deducted. Labor laws vary by jurisdiction on which breaks are paid. Shift differentials are premium pay rates for working undesirable hours, typically nights, weekends, and holidays. US night shift differentials typically range from 5-15% above base pay. Accurate shift hour tracking is essential for calculating these premiums. Occupational health research shows that shift workers face increased risks of sleep disorders, cardiovascular disease, and workplace accidents. The circadian rhythm disruption from rotating shifts is particularly problematic. Many industries now limit consecutive shift hours and mandate minimum rest periods between shifts. The European Working Time Directive limits average work weeks to 48 hours and requires 11 hours of rest between shifts. Three-shift systems divide the 24-hour day into three 8-hour blocks (typically 06:00-14:00, 14:00-22:00, 22:00-06:00). Twelve-hour shift systems use two 12-hour shifts, often with rotating patterns (e.g., 4 on, 4 off). Each system has trade-offs between coverage, employee well-being, and overtime costs.