Time Zone Calculator
Adjust the inputs below. Results update as you type.
How it works
UTC (Coordinated Universal Time) is the reference: offsets range from UTC−12 (Baker Island) to UTC+14 (Line Islands). Daylight saving time shifts some zones by 1 hour seasonally—not all countries observe it. India (UTC+5:30) and Nepal (UTC+5:45) use non-standard half/quarter-hour offsets. For recurring meetings, specify time zone (not just UTC offset) to handle DST transitions correctly.
Input guidance
- Confirm date/time/unit settings before comparing outputs.
- If a task has optional fields, run both with and without them to understand impact.
- Save scenario variants when making practical decisions.
The formula
Converted time = source time + (target UTC offset − source UTC offset). Daylight saving shifts offsets by an hour in many regions.
Worked example
9:00 AM in New York (UTC−5) is 2:00 PM in London (UTC+0), a five-hour difference.
More examples to test
- Quick-pass example: run default assumptions for a first estimate.
- Refined example: update one assumption at a time to isolate impact.
How to interpret results
Use outputs as operational estimates and pair them with local constraints, business rules, or provider requirements.
When this can be inaccurate
Utilities can miss local policy details, special-case rules, and environment-specific constraints.
Change history
- July 2026: Quality-reviewed for publication with formula checks and explanatory copy updates.
Site-wide corrections also appear on the corrections log.
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General recommendation, not professional advice.
Frequently asked questions
How do time zone conversions work?+
Each zone has an offset from UTC. Convert the source time to UTC, then apply the target zone's offset to get local time there.
How does daylight saving affect this?+
Many regions shift their offset by an hour seasonally, and not all at the same time, so the gap between two cities can change during the year.
What is UTC?+
Coordinated Universal Time, the global reference. Time zones are expressed as positive or negative offsets from UTC.
Why are outputs slightly different from another tool?+
Different tools can use different rounding rules, default assumptions, and treatment of edge cases.
How can I improve estimate reliability?+
Use verified inputs from real records and re-run calculations after major assumption changes.