How Timezone converter works
Timezone converter takes a specific date and time in one IANA timezone and tells you the matching wall-clock time in another, "3pm in New York is what time in Tokyo?". It accounts for daylight saving on the exact date you choose, so the result is correct year-round.
If you only need the current gap between two zones rather than converting a specific moment, the Timezone difference tool is more direct. It uses the IANA timezone rules built into the browser, so each conversion reflects whether DST is in effect on the specific date you pick.