How to use this calculator
Compare a UTC instant or enter local wall time in the first IANA timezone. Both locations are resolved at the same instant. Nonexistent clock times are rejected; repeated times require an explicit earlier/later choice. Results include full local calendar dates/times and UTC offsets.
- Enter entered time represents, utc date and time, first timezone (iana name) and review the remaining options.
- Select Calculate or change a value to update the result. Read the result label and units before copying.
- Use Reset to restore the worked starting values.
Formula and method
Timezone rules use the browser IANA database. Local-time resolution checks nearby offset regimes and round-trips candidate instants; no fixed-offset guess is silently accepted. Historical data and future timezone laws may change.
Worked example
At 12:00 UTC on July 1, 2026, London is 5 hours ahead of New York.
Questions about time zone difference calculator
Why can the time difference change during the year?
Locations may change UTC offsets on different dates or may not observe daylight saving. Choose a UTC instant or a source-local date and time. The local mode rejects nonexistent clock times and lets you reject an ambiguous time or select its earlier or later occurrence. Both zones are compared at the resolved instant.
What assumptions should I check?
Timezone rules use the browser IANA database. Local-time resolution checks nearby offset regimes and round-trips candidate instants; no fixed-offset guess is silently accepted. Historical data and future timezone laws may change.
Are my inputs saved?
Calculations run in your browser. We store only tool IDs for favorites and recent tools. A calculation link contains your inputs only when you explicitly choose to copy one.