Windows has several built-in apps that may look useless but offer helpful hidden features. For instance, the calculator app can also calculate the difference between two dates and convert basically any unit of measure, including time, energy, temperature, distance, mass, and even currency.

Windows Alarms & Clock app can calculate the time difference between two locations, even into the future. Open the app, click the Clock tab, and select the + icon at the bottom to add locations. Click the Compare icon to open a timeline. As you scroll across the timeline, the time changes on the map points, allowing you to keep track of time differences more easily.