At the moment, CalendarBudget supports multi-currency by checking the browser locale.
If you go to you browser settings and look for language settings, you’ll find you can set your browser to the country and language you live in.
For example, if you live in UK, you’d want to set the locale to en_GB, which is the UK English. When you do this, the currency in CalendarBudget should change to pounds. If you want specific instructions for your browser, let me know which browser you are using and which country/language you are trying to get going (and what currency) – I’ll provide instructions for you.