UTC (Coordinated Universal Time) is the reference clock for the entire world. If you’ve ever seen a schedule written as “14:00 UTC,” that’s the universal baseline. Every local time zone can be expressed as an offset from UTC, such as UTC+8 or UTC-5.
Before global communication, each city could keep time based on the sun. But modern travel, aviation, the internet, and international business require a consistent standard. UTC provides a shared “clock” so systems and people can coordinate without ambiguity.
Local time changes by region and sometimes by season. UTC stays stable and does not switch for daylight saving time. That’s why software logs, flight plans, and global services often store timestamps in UTC, then convert to local time for display.
Time zones are typically defined by their UTC offset. If your local time is UTC+9, it means your clock is nine hours ahead of UTC. If it is UTC-5, it is five hours behind UTC. Offsets may change in regions that observe daylight saving time.
When scheduling across countries, start with UTC, then convert for each participant. This reduces mistakes when daylight saving time changes in one region but not another.