Time Zone Converter

How does this time zone converter function?

This is a time tool that is based on the time zone map of the world and finds the time difference between any of the locations listed in the form. All you have to do is choose the region, be it from Africa to South America and whether you want to pick a country or a city in that region to use. It covers the international time in all the countries in the world plus some of the most important dependent territories and also takes into account daylight savings time (DST).

If you take a look at the form above you will see that 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 and for each region you need to decide if you prefer a country or a city. Once you have selected the region the second selection for location will display the countries or the cities in the region you chose in alphabetical order for you to find the desired place easier.

As you press calculate the time zone converter will find your locations in a complex database of the world time zones, check whether it needs to take into consideration the existence of a daylight savings time and will then calculate the time zone difference between your two locations and return you with the exact time in the second place you chose. This is the rule of thumb for any international conversion: "time in zone B" = "time in zone A" − "UTC offset for zone A" + "UTC offset for zone B".

Why you may need to use a time zone converter?

Surprisingly enough there are many situations in which you can find yourself in need for a quick check of an international time in a given place and the easiest way is to use such a tool. Maybe you are going on a vacation in a foreign place and want to know exactly the local time there or you need to call someone overseas. You can even find yourself in the situation to make phone calls or conferences abroad and you need to schedule them at an appropriate time for all the participants and the biggest the time difference is the harder will be for you to manage things without knowing exactly the local time there. Also knowing important world time zones can help you make connections between time and geographical position of certain countries making it easier for you to remember where some place is or simply check how the daylight savings time system works in other places.

Coordinated Universal Time (UTC) definition

This represents the modern civil time and has been defined since January 1972 to follow the International Atomic Time (TAI) with an exact offset of an integer number of seconds. Greenwich Mean Time (GMT) is an older standard, adopted starting with British railroads in 1847. GMT was calibrated to the mean solar time at the meridian passing through the Royal Observatory in Greenwich, UK. This time keeping method is less exact than the UTC because the rotational period of Earth is not perfectly constant and the duration of a second would vary if calibrated to a telescope-based standard like GMT. 

Since 1972 all official services have broadcast radio time signals synchronized to UTC, a form of atomic time that includes leap seconds to keep it within 0.9 seconds of this former GMT. Within this implementation most nations began to use the UTC standard when defining their zones instead of the former GMT definition. A UTC time offset is the amount of time subtracted from or added to UTC to get the current local time for a specific location. Offsets from UTC are written in the ±[hh]:[mm] format.

Understanding time zones

This is a region on Earth that keeps the same standard time. The time zone map shows that Earth is split up into areas that are mostly one hour apart. The local time for each region is an offset from UTC or the former used GMT. Many locations change the offsets during summer months to define the usage of Daylight Savings Time (DST). Time zone boundaries are marked by the lines of longitude for each time zone being at 15° towards west or east the preceding one. The reference point for UTC is still the Greenwich Meridian also known as the Prime Meridian which has the longitude of 0°. Local time is then calculated adding an hour for each 15° heading east and subtracting an hour for every 15° heading west.

About Daylight Saving Time (DST)                                                     

DST is also known as summer time and represents the practice of advancing in the summer months so that afternoons have more daylight and so electricity costs would be reduced. Clocks are advanced an hour in spring and adjusted backward an hour in autumn. Daylight savings time is mostly used to save energy and reduce the use of artificial light during evenings.

The one hour shift occurs at a specific date established by each country and the 02:00 local time shifts to 03:00 local time in spring and from 03:00 to 02:00 in autumn. To know how the clocks go just remember “spring forward, fall back”.

Modern DST was first proposed in 1906 and spread in the wartime as a measure to reduce coal usage.

The practice of it 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.

World Time Zones (UTC offsets worldwide) chart