Coolendar is described as 'Is not only a calendar or a to-do list: it's a whole new planning experience! We believe it is time for a new level of planning software. Something simple that works for you, without the noise of handling a calendar or tasks app' and is a todo list manager in the office & productivity category. There are more than 100 alternatives to Coolendar, not only websites but also apps for a variety of platforms, including Windows, iPhone, Android and Mac apps. The best Coolendar alternative is Google Calendar. It's not free, so if you're looking for a free alternative, you could try Google Calendar or Todoist. Other great sites and apps similar to Coolendar are Microsoft Outlook, ToDoList, eM Client and Org mode.