Calzone is a free Chrome add-on developed by Rapscallion Labs that allows you to convert between timezones while you write or read by simply highlighting text. With Calzone, you can easily convert any text that contains a time, with or without a timezone.

One of the key features of Calzone is its ability to store a list of recently used timezones, making it easier for the extension to guess which timezone you're interested in converting into. However, you also have the option to manually specify the timezone you want.

Calzone supports a wide range of time formats, including 12-hour and 24-hour formats, as well as different timezone abbreviations. Whether you're working with a time like "5pm" or "17:00 PT", Calzone has got you covered.

It's important to note that after installing the Calzone extension, you will need to reload any tabs you had open in order for it to work properly. Additionally, please be aware that all extensions are disabled on Chrome Web Store pages, so make sure not to test the extension on that page.