To calculate the time difference: 1. Enter the first time and select its time zone 2. Enter the second time and select its time zone 3. The calculator will show the difference in hours, minutes, and seconds For example, if you want to know the difference between 9:00 AM in New York and 2:00 PM in London, the calculator will show a difference of 5 hours. You can also calculate the difference between times on different dates to find out how many days, hours, minutes, and seconds separate them.

Yes, our calculator handles time differences across the International Date Line correctly. When calculating time differences between locations like Los Angeles and Tokyo, which are on opposite sides of the International Date Line, the calculator accounts for both the time zone difference and the date change. For example, when it's 8:00 PM on Monday in Los Angeles, it's already 12:00 PM on Tuesday in Tokyo - a difference of 16 hours forward, not 8 hours backward.

A negative time difference means the second time is earlier than the first time. For example, if you calculate the difference between 3:00 PM in London and 10:00 AM in New York, you'll get a result of -5 hours, meaning New York is 5 hours behind London. This is useful for understanding which location is ahead or behind in time, especially when planning international calls or meetings.

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks and time. It's crucial for: 1. International time coordination - UTC provides a consistent reference point for all time zones 2. Avoiding daylight saving time confusion - UTC doesn't change with seasons 3. Scientific and technical applications that require precise time synchronization All time zones are defined as offsets from UTC (e.g., Eastern Standard Time is UTC-5, meaning 5 hours behind UTC). Our calculators use UTC behind the scenes to ensure accurate time conversions and calculations regardless of daylight saving time or other regional time variations.