¿Cuándo en el Mundo? is an online resource for checking calendars, dates, holidays, and local times around the world. Its calendar pages cover individual years and months, with options to select a country and adjust calendar settings. Visitors can browse calendars for countries across Europe, the Americas, Africa, and beyond, including Spain, Mexico, Colombia, the United States, and the United Kingdom.

The site also offers printable calendars and annual planners that users can generate as PDFs, with a choice of designs. Its world clock provides current times for capital cities worldwide and can be sorted by country, city, or time zone, with 12-hour and 24-hour display options. Visitors can also explore capital cities by region, including Europe, Asia, Oceania, Africa, and the Americas.

For international calls, ¿Cuándo en el Mundo? provides information about dialing codes, helping users find the codes needed to call other countries or call home from abroad. Together, these tools make the website a practical reference for planning dates, checking time differences, and preparing international calls.