123 Calendar is a user-friendly calendar app designed for iPhone users, offering a convenient overview of weekly events in a single glance. The app allows for easy navigation with simple left/right swipes to zoom in and out of the week view across three levels of zoom. Each day's schedule is displayed prominently at the top of every line, eliminating the need for excessive zooming.

Users can effortlessly manage events by adding, moving, copying, and deleting them with intuitive controls. Customizing events with personalized colors and shading is a breeze, enhancing visual organization. The app provides the functionality to create filters that automatically highlight specific events based on keywords, streamlining event management.

123 Calendar enables users to group calendars for quick access and organization, allowing for easy toggling between visible and hidden calendars. The top bar feature further enhances user experience by highlighting events matching filters or specific calendar groups. Notably, this app is free to use without intrusive ads, ensuring a seamless and uninterrupted experience for users.