旧シフト手帳 is a productivity application designed for iPhone users who work in shift-based jobs, such as call centers, hospitals, and supermarkets. This app allows users to quickly calculate their shift wages based on hours worked and hourly rates, making it an essential tool for both shift workers and regular employees needing to track overtime. Key features include automated wage calculations that account for early departures, overtime, night shifts, and holiday work, ensuring accurate payroll management.

The app also provides various functionalities such as alarm settings for shift reminders, an easy-to-use calendar that reflects holidays, and the ability to send shift schedules via email to friends. Users can input simple notes for each day, manage days off, and generate detailed monthly and yearly payroll reports. With widget support for quick access to shift information and URL scheme functionality, 旧シフト手帳 streamlines shift management effectively.