Time Zone Calculator

How does the time zone calculator work?

This time tool puts to use the information from a time zone map of the world to provide a quick world time converter for countries. Depending on the period and whether your chosen countries use the daylight savings system you will receive the current time in the country you want also taking into account the DST.

All the fields in the left column can be modified and that the right column is the area in which the results will appear once you make your choices and press calculate. The first two fields are the current date and time and you can change according to your needs. Below are two lines in which you need to choose the starting point for the international time conversion and the location for which you want to find the corresponding time. In each of the two lines you first need to choose the region in order to narrow your choice. You can choose from Africa, Asia, Australia, Caribbean, Central America, Europe, North America and South America. Once you decide for a region the second two selections will ask you to choose the countries you want to make the transformations for. Time zone conversions are based on the following formula: "time in zone A" − "UTC offset for zone A" = "time in zone B" − "UTC offset for zone B".

When do you need to use a time zone calculator?

Here are some of the situations you might find yourself in need to calculate the time difference between two countries:

• When you’re going on a vacation in a foreign place and want to know exactly the local time there.
• When you need to schedule more than one flight in the same day.
• When you need to call someone overseas.
• When making business phone calls or conferences abroad and you need to schedule them at an appropriate time for all the participants.
• Educational purposes, a quick way to retrieve a country in a specific time zone.
• Check how the daylight savings time system works in other places.
• The biggest the time difference is the harder will be for you to manage the calculations without knowing exactly the local time in the places you’re considering.

Coordinated Universal Time (UTC)

Greenwich Mean Time (GMT) was the first time standard adopted in 1847 and followed time using telescopes and was calibrated to the mean solar time at the Royal Observatory in Greenwich, UK.

Until 1972 all time zones were specified as an offset from GMT but then all official time services have broadcast time signals synchronized to UTC that represents the basis for the modern civil time and follows the International Atomic Time (TAI) with an exact offset of an integer number of seconds. Most countries now define their local standard time relative to UTC.  Time offsets represent the amount of time added to or subtracted from UTC. Time Offsets from UTC are written in the ±[hh]:[mm] format.

Time Zones

These can be defined as geographical regions of Earth than can be observed on a world time zone map. Most time zones are one hour apart and compute local time as an offset from UTC or GMT. Each boundary is established at 15° longitude lines from the preceding time zone. The reference point for UTC is the Greenwich Meridian (the Prime Meridian), which has a longitude of 0°. Local time is UTC plus the current time zone offset for the locations situated eastern to the meridian and UTC minus the current time zone offset for the locations situated westward.

Daylight Saving Time (DST)                                                     

DST represents the practice of advancing clocks one hour ahead during spring and then going back to the standard time in autumn. To know how the clocks go just remember “spring forward, fall back”.

This system is used in several countries in order to make a better use of sunlight during summer months, save energy and reduce the use of artificial light during evenings. Each country has established dates in which to make the switches for the following years. The practice of DST is more used in the northern and southern hemispheres than around equator since sunlight changes are minimal around equator. In the northern hemisphere clocks change and the daylight savings time starts between March-April and then ends somewhere between September-November. In the southern hemisphere DST starts between September-November and ends between March-April. The one hour shift occurs at 02:00 local time shifts to 03:00 local time in spring and from 03:00 to 02:00 in autumn.