2026-05-08 / 4 min read
UTC vs GMT: What Is the Difference?
A clear guide to UTC, GMT, offsets, and why timezone converters often use UTC as the reference point.
Short answer
UTC is the modern global time standard used by computers, aviation, science, and time APIs. GMT is a historical time standard tied to Greenwich, London, and is often used casually to mean UTC+00:00.
For everyday planning, UTC and GMT often appear identical. For technical accuracy, UTC is the safer reference.
Why this matters for scheduling
When you compare cities, the real question is not only the base offset. Daylight saving time can move local clocks forward or backward while UTC stays stable.
That is why a date-aware converter is better than a static offset table.