How it works
The conversion uses the Intl API, already built into every modern browser, which contains the official time zone database (IANA Time Zone Database) — including each region's daylight saving time rules, applied automatically based on the chosen date. No paid API or external server connection is needed.
About daylight saving time
Since daylight saving rules depend on the date (not just the zone), the same time zone can have different UTC offsets in January versus July, for example. The tool automatically accounts for this based on the date you picked.
Frequently asked questions
Is the date I enter uploaded to a server?
No — the entire conversion happens locally in your browser, using JavaScript's native Intl API.
Does the tool account for daylight saving time?
Yes, automatically, based on the chosen date and each time zone's official rules.
Why is the time zone list so long?
On modern browsers, we use the full list of time zones recognized by your system (hundreds of options); on older browsers, we show a shorter list of the most common ones.