The year shown here comes straight from your device’s system clock, so it’s always current — no lookup or calculation needed beyond reading the date your device already knows.
In the Gregorian calendar, which is the calendar used by most of the world for civil and business purposes, the year always resets on January 1st, everywhere that calendar is followed. That’s a convention, not a law of nature — plenty of other systems don’t work that way. The traditional Chinese calendar, for example, is lunisolar and marks its new year on a different date each year, typically landing sometime between late January and mid-February. Businesses and governments often layer a separate “fiscal year” on top of the calendar year for accounting purposes, and that fiscal year frequently starts on a date other than January 1st — some organizations use July 1st, others October 1st, depending on local convention.
So while the number this page displays is simple, it’s worth remembering it’s specifically the Gregorian calendar year — the one tied to January 1st — rather than the only possible way a “year” can be counted.